SC

ENCE \.

THE OPPORTUNITY OF ANATOMY1

IT has been the custom of the past few years for
the person whom you have chosen as your presiding
officer to give in this hour some comprehensive sur-
vey of his own research. But last year you gave a
generous allotment of your time to a symposium on
the subject in which I am especially interested. At
that time I presented the work of my colleagues and
myself, it is true in an incomplete form, but as OUT
experiments have since been analyzed and published,
I propose, with your permission, to speak on a more
general topic. I wish to return to an earlier custom
of this society and consider the general subject of
teaching. This year marks the end of my career as
a teacher: I have taught my last class, I have ceased
to be a professional teacher, but remain a professional
student; but I have taught for twenty-six years,
twenty-three years in a medical school, with such
pleasure that I wish to record some of the changes
which I have personally lived through in the teaching
of anatomy.

The relation of anatomy to medical research is to
be my special topic, for both in its position at the
beginning of the medical course and in the nature of
its subject-matter, anatomy has facilities unsurpassed
for turning the minds of students toward research.
From the programs of our `meetings it is clear that
gross anatomy is enlarging its field for research into
the domain of anthropology, that neurology is at the
present time one of the most brilliant subjects for
research, in its almost untrodden field for the corre-
lation of structure and function, but it is specifically
of histology that I wish to speak this morning, to the
thesis, that, in histology, one has a rare opportunity
to teach knowledge in its growing zone. That is the
definition with which Havelock Ellis in his most fasci-
nating new book, "The Dance of Life," has illumi-
nated the relation of science to modern education.

When I began the teaching of histology, twenty-
three years ago, the. subject was a minor discipline.
Histology began with the discovery of the cell, and
through its early period it was the isolated cell that
dominated its subject-matter; but the cell, isolated
by methods of maceration, dilute alcohol for the epi-
thelial cells and weak acids for muscle, had been dead
long before it was studied and so we had only gen-
eral concepts concerning its form and its relation-

IPresidential address given before the American
ilssociation of Anatomists, 1925.


SCIENCE

  [VOL. LXI, No. 1585

ships. The microtome was then introduced and we
began to study sections. That marked the next phase
of the study of histology, namely, the survey of all
the organs of the body, in order to learn the general
topography of the tissues. It was during this phase
of the subject that text-books began to appear.  When
I began teaching histology we had these two tech-
niques. We gave quite simple exercises with isolated
cells of each type and about three sections each day
to be stained, mounted and studied by the student.
We had also frozen sections which we studied mainly
for the fibers of the connective tissues. We used them,
here and there, to analyze the structure of an organ ;
for instance, following the work of His, we shook
frozen sections of lymph glands in a test tube and
speculated on why the follicles fell out and the rest
of the framework remained. When I took charge of
our `course in histology, Dr. Mall gave me only one
direction, but advised me to read two books, both of
them by English teachers-one, Beale's "How to
Work with the Microscope,"2 and the other a little
book by Miall on "Thirty Years of Teaching."s  The
book of Beale is not a cut-and-dried text-book, with
a mere statement of facts, but is the record of a man
who had used a microscope with joy to find out things
concerning which he was intensely curious.

Miall's book has charm.  He was a teacher of biol-
ogy in the Yorkshire College and his concept of teach-
ing was to help students to love their work. To quote,
"Lecturing aims at giving information, teaching aims
at discipline. To both teacher and student the way
in which a result is got may be far more important
than the result itself. . . . When two biologists
meet, they tell one another things, but they don't offer
discipline to one another. The professor and an
aavmmd class should be on something like the same
terms." Or again, "The spirit of inquiry is only to
be communicated by those who have it, who habitually
inquire themselves."

The specific counsel which Dr. Mall gave me was
that in outlining any plan of work for students one
should never make the directions so specific as to rob
the student of his pleasure in discovery and make him
mechanically follow a definite procedure.  This is the
flaw in most of the formally published courses, that
they tend to destroy for the student all the pleasure
of personal discovery. It is clear that the nature of
instructions to be given to students must vary to some
extent, indeed perhaps to a marked extent, with the
nature of the material to be handled. If material
is rare or fragile or involves the use of anesthetized
animals, then the directions must be specific, but there

2 Harrison, London, 1868.
3 L. C. Miall, professor of biology in the Yorkshire
College, Macmillan and Co., London, 1897.

are certainly two subjects in the premedical sciences,
namely, histology and pathology, where material car,
be 80 unlimited that the student can be given great
liberty and be taught wholly in the spirit of finding
things out for himself.

I have said enough to make it clear that it is of
histology in its growing zone that I wish to speak.
We have passed through two phases of histology,
through the primary analysis of its elements and of
how they are put together to form organs and we
have now a third and entirely new type of subject.
matter. There is, it seems to me, no longer any need
of an elementary course in histology, in a medical
school for which the entering students have been ade-
quately prepared in biology and in the use of the
microscope. I am well aware that many of you may
not agree with this idea, but it is my real conviction
How else shall we progress in education unless we
condense those things which have become so well
known that they have been simplified and teach knowl-
edge in its growing zone. By an elementary course
in histology, I mean one in which the major part of
the work consists in learning to describe and identify
sections; this is the finished part of our subject, not
its zone of growth. The subject-matter of this part
is simple, is well worked out in text-books and can be
readily mastered by the student without much aid. It
seems to me that, in each subject taught to advanced
students, the teacher should make a clear analysis in
his own mind of that part of the subject-matter which
is stat& well known, well presented in text-books,
and hence readily available to the students' own in-
itiative, and that part which is dynamic, concerning
which there are marked diierences in opinion by ex-
perts, and concerning which he may confidently expect
development in the coming years. There are assuredly
dangers involved in regarding any body of scientific
knowledge as static, but at the risk of wearying YOU
I wish to make quite specific the type of material
which seems to me feasible subject-matter for a course
in histology at the present time, and I will take four
examples from my own experience. In presentin
these examples, I have also in mind that when a Cer-
tain foreign commission visited our laboratory to
study our methods of teaching, it was clearly in the
minds of our guests that, without the specific matei+l
of modern biology, histology was lacking in adequate
subject-matter for medical students. The frank dis-
cussion of such differences in plans for education I
consider of value to teachers ; it is obvious that we
would give modern biology as the preparation *Or
Bistology.

My first example will be the spleen. In the first
place, I would give to each student a se&ion of human
spleen and of the spleen of one or two animal tYpes


UY 15, 19251                  SCIENCE                         501

in aavmce. It has been our custom to give the set-
tions to be stained and mounted by the students at
the &se of the period before the subject is taken up
in class; that assures ample material in the way of
getions to be used for reference. For the work on
the spleen the student would have, in his own collec-
tion, not only sections of the spleen but aIs0 of hemal
+nds and of lymph glands. Moreover, one of his
sections would be a mesenteric lymph gland in which
he had 5lled the lymphatic sinuses with ink by inject-
ing the lymphatic. vessels of the intestine. The spe-
cific work on the spleen would then be directed toward'
three ideas-what is the nature of the circulation in
the spleen, what kind of endothelium lines its veins
snd what are the free cells in its pulp. Not one of
these problems can be analyzed without experiment.
1 should begin with Mall's crucial experiment to
nuderstand the remarkable nature of the splenic cir-
culation. To prepare the material, take a dog the
dsy before the class exercise and tie off all the splenic
veins, slip the organ back into the abdominal cavity
for half an hour, at the end of which time the animal
will have bled into its own spleen until the organ is
twice its normal size. Then tie off the arteries and
fix the entire organ in formalin without any rupture
of its capsule. A second similar experiment, in which
all the vessels are cut before fixation brings the organ
back to the normal size, very quickly makes a con-
vincing comparison. The class then would have
frozen sections made from the two experiments; in
one, both the pulp and the veins of the pulp will be
engorged with blood ; in the other both will be empty.
This, then, would give the material from which to
discuss how the splenic pulp can be so completely
filled and then so quickly emptied. In a lecture one
could then show why the question of whether there
were specialized channels in the pulp' between the
arteries and the veins of the pulp dominated research
on the spleen so long and how the work of Weiden-
reich and Mall had finally demonstrated that it is the
splenic pulp as a whole that intervenes between artery
and vein. In the frozen sections of such material
there will be occasional places in which the blood has
run out of a vein of the pulp, and such places can
be used to illustrate the contrast between the pulp and
its veins; but for this purpose we have in Baltimore
some beautiful complete injections of the veins of the
splenic pulp, made by Dr. Mall and never illustrated
in his publication. In these preparations he succeeded
in filling the pulp so completely with one substance
and the veins with another that both are quite distinct.
Our next topic would be the nature of the endo-
thelium lining the empullae and the veins of the pulp;
sud here we would use the technique introduced by
Nollier, who has shown that, when the spleen is 5xed

after a moderate distention produced by circulating
the fixing fluid through the organ and the sections
stained with an intense protoplasmic dye, such 88 acid
fuchsin, the endothelial lining of the veins can be seen
to be riddled with holes.  Each student would receive
such a section for his collection and could then 5nd
for himself the peculiar, widely fenestrated endo-
thelium of the veins of the splenic pulp and could
then more easily understand from such evidence how
the animal can bleed into the splenic pulp and then
empty the pulp so completely. We would give out
one se&ion in which a very little. ink or Prussian blue
had been injected in one quick spurt into the splenict
artery. Such an injection of the splenic arteries rep-
resents an extravasation, if you will, into the splenio
pulp, or in other words shows that the splenic pulp
is in lieu of a capillary bed. These points we regard
as feasible to demonstrate and that after such a pres-
entation of the nature of the entirely unique circula-
tion of the spleen, an organ in which there is nothing
but a framework and a vascular bed, the student could
take an ordinary section of the spleen, find its trabecu-
lae and think of the meaning of its bands of muscle,
identify the Malphigian corpuscles and see for him-
self why it is that the relation of the splenic pulp to
the veins of the pulp can not be analyzed from the
hay of normal sections alone.

We would give one more preparation of the spleen,
perhaps one of the most instructive, namely, a section
of a spleen from a rabbit which had received repeated
injections of trypan blue, or better of carmine, until
the veins of the splenic pulp had become so clogged
with cells, in our view, endothelial phagocytes or clas-
motocytes, that the veins stand out in a section even
when seen with the low power of a microscope.  Here
we would help the student to follow the endothelium
of the sinuses and to see the clasmatocytes both within
the sinuses and free in the pulp and then give him a
chance to make his own judgment as to whether
Azchoff's term of "reticula-endothelial apparatus" is
signi5cant or confusing. We believe that reticulum
and the free endothelial derivatives are both quite dis-
tinct in the pulp, but the student will surely 5nd that
the concept of a reticula-endothelial apparatus so
dominates opinion in pathology to-day that he may
well spend much time in .studying this section and
getting his own ideas on this subject.

The second topic which I wish to present is the
nature of the cells of the connective tissues as they
can be analyzed by the vital technique.  Here I should
begin with the experiment of Professor Maximow in
the analysis of the 5broblasts from the clasmatocytes
of the difl?use connective tissues by the use of vital
neutral red. In the work which Dr. Cunningham, Dr.
Doan and I have just published on the cells of the


SCIENCE

[VOL. LX& No. 1585

connective tissues, we have given a technique for  with tuberculosis, in which it will be possible to sur-
studying the living cells of the splenic pulp.  If one  vey the whole subject of the relationship of clasms-
takes a finely drawn out glass pipette and plunges it  tocytes, monocytes and lymphocytes in this disease.
into the spleen of a rabbit while the circulation is   The next subject which I wish to discuss is the
active, blood and free cells will run up into the  teaching of the pancreas.  Here we would follow the
pipette and one can then make a preparation entirely  work of Dr. Bensley. We would give our student
comparable to a blood film.  These are made either on  ~ecttious of the pancreas, selected in different func-
a coverslip for fixing and staining with the ordinary  tional states, as Dr. Bensley has taught us, to shorn
technique, or on a slide which has been coated with  the maximum of the basophilic substance and the
a film of vital neutral red and Janus green combined.  maximum of zymogen granules. For the class work
In such a preparation from the spleen the cells will  we would give a bit of the fresh pancreae of a rab-
differ according to whether the pipette entered the  bit, and sometimes a second preparation after an in-
pulp or a follicle. If the specimen comes from a  jection of pilocarpin to show an emptying of the
follicle, lymphocytes will predominate, but if from  zymogen granules. We would then give the pancreas
the pulp, then there will be two predominating types  of the guinea pig with the vital injection of neutral
of cells, the large free clzismatocytes, filled with red  red for the islets, have the experiment of the count-
blood-cells or their dhbris, and the monocytes with  ing of a small bit of the organ, and hunt for the
their beautifully stained rosettes and outlying mito-  individual islet cells either in the septa or from more
chondria. This is not an easy technique to give a large  completely teased bits of the tissue.  On the next day
class, because the spleen will not stand an unlimited  we would give the vital injection of the Janus green
number of such punctures, but one animal may be  for the mitochondria, the beautiful demonstration of
used for about fifteen students. These two types of  the controacinar cells by the injection of methylene
cells, the clasmatocyte and monocyte, can perhaps be  blue and finally the mixed injection of pyronin and
most easily demonstrated to a large class by making  Janus green. Ever since Dr. Bensley published his
a vital film from a scraping of a freshly cut surface  studies on the pancreas we have tried for a satisfac-
of the lung. For this experiment we should inject  tory demonstration of the blind ducts to the islets,
a little ink with a hypodermic needle into the trachea  and this year we got such a clear demonstration of
of a guinea pig the day before, following the work  the point that no student could miss it. By chance
of Dr. Wislocki, and from this material we should  we made an injection of the pyronin of double
tlnd no diiculty in securing for every student a suc-  strength combined with Janus green and let the prep-
cessful preparation. I may say in passing that the  aration stand a half hour; then every islet was clearly
method of puncture entirely solves the question of  stained in the Janus green and the plexus of the ducts
giving a class good films of bone marrow, both for  stood out beautifully distinct in the pale red of the
fresh material and for fixed smears.  It does not mat-  pyronin. I think that no student could look at the
ter in the least that in our own laboratory there are  demonstration of the living centroacinar cells with
two' opposing views concerning the interpretation of  their processes reaching far out between the acinnr
such specimens, we believing that the clasmatocytes  cells without realizing how inadequate ordinary see-
and monocytes represent two different functional  tions are to demonstrate them. After a student has
strains of cells, while Dr. and Mrs. Lewis believe that  made such a study of living pancreatic cells, sections
they are one strain. Indeed such differences in inter-  may seem a little dull to him, but they will serve t*
pretations are as stimulating and valuable to our stu-  remind him of what the pancreas really looks like and
dents as they are to ourselves. When you can bring  we are confident that the student would still hsve
out such points of difference of real significance to  some vivid memories of the real organ in his mind
the study of what cells .&ually do, then the student  to aid him in physiology and pathology.
knows that he is studying a growing. zone of medi-   The fourth illustration which I wish to give is fro*'
cine.  Such difIerences are only of value to a student  the reproductive system. Our material for this sub-
when both points of view are presented to him with  ject would depend on the work of Ancel and Boom*
entire fairness. For our own work we regard that  Stockart, Evans and Long, and Corner. It happens
the separation of these two strains of the cells of the  that the laboratory in Baltimore is near a slaughter
connective tissue is of value because we were also  house and so an abundant supply of material from the
working on tuberculosis last spring and obtained evi-  pig is available. We would give each student or each
dence which convinced us that it is specifically the' two students an entire uterus and ovaries from a Pig.
monocyte which becomes the epitheloid cell in tuber-  Then, following the work of Corner, we would hnrc
culosis. This concept seems to us to open up an  each student study the ovary with reference to it-$
entirely new range of experimentation in connection  condition in the oestrous cycle and whenever an ovary


J[ap 15,1925]

SCIENCE

503

,,.@ found with a recently ruptured follicle, the tubes
or the utemz would be washed out by Comer% tech-
nique and the ova recovered. Frozen sections would
be made from a wrpus luteum selected to show the
flestest amount of fat and the sections stained with
&dsn III. On the next day each student wonld
receive a pregnant uterus and study the foetal mem-
branes and placentation.  In our wurse this day's
,& was developed by Dr. Wislocki, who gave a
demonstration of comparative placentation from `his
own work. Each person teaching in a course should
thus enrich it with the material of his own research.
After such a study in the laboratory the student
,co&l not find it hard to study sections of ovaries;
,,ll sections of the ovary and of the uterus of what-
ever animal used should now be given out with a
rNord of what phase in the cycle they represent.  It
m to me anatomiste have contributed more in the
p& few years to the analysis of the reproductive
cycle than all clinical experience put together.
I truzt that you will pardon the detail with which
1 have given these illustrations; they show how the
material for a wurse in histology can be built up
from research and they represent mtiterial that is
entirely feasible from the standpoint of experience.
It is all readily obtained and not too ditilcult to ana-
lyze. I have intended these examples to show the
difference between an elementary and an advanced
course in histology. Such plans for material I am
convinced should be frequently changed in any coume,
if it is to have life. and vigor.  Sometimes a wholly
new arrangement of the sequen= of a course will.
give new plans of presentation, or a new technique
mill develop in research that will give a whole new
range of material. Material should be frequently,
dropped from a course and new specimens brought in.
In a word, it is of more importance that the material
of a course should be thoroughly interesting to the
teacher himself than that he should try to cover the
entire ground of his subject each year.
I am quite aware that besides the general criticism
of thii concept of the type of course in histology,
there will be the direct criticism of the @atholdgist
that in such a course the student does not get such
8 specific knowledge of the characteristics of normal
human material as to give him a nice discrimination
of early pathological changes. In this connection it
is my judgment that courzes should not be too closely
dovetailed because in the medicsl school the &dent
@im by having similar subjects from different view-
points. I think that the histologist can better atEord
to Use sections from different animals so selected as
to demonstrate function in the clearest way possible
Or else selected to show variations in strnctures of the
tierent experimental animals, such aa the marked

variation of bronchial muzculature, that are at the
present time sign&ant in medical research and leave
to the pathologist the human material, over which he
has such a vastly greater control and concerning
which he is almost certainly more competent to judge.

It has come to my attention in lata years that the
directors of physical training in all secondary schools,
even those for girls, receive a higher salary than any
of the very most successful of those teachers who are
concerned only with the intellectual side of education.
I have finally found some comfort in this unwelcome
fact in the thought that at least no teacher of physical
exercise commits the cardinal sin of thinking that he
can develop the muzcles of his stndents for them by
exercising his own musclez.  I want to stress the idea
that .the value of a laboratory to the student is that
it is a place where he can work.  The &dent could
get facts more quickly out of a book; a text-book
that tends to take a student away from his microscope
is a poor aid to a wurse in histology.  Moreover, the
teacher does not need to point out to the stndent the
things in his section which the student can find for
himself. For example, when the student is studying
blood-vessels the teacher may show him a corrosion
of the organ and call his attention to the number of
orders of vessels in a given layer; he should show
him how to dissect with the focusing screw of the
microscope the coats of vessels in some such mem-
brane as the pia mater, but he does not need to dnd
for him the vessels in sections.  Meet of all the teacher
does not need to concern hiilf with aiding the stu-
dent to memorize; for that the student can be entirely
responsible himself. If I were to give a young teacher
advice concerning the directing of a laboratory course,
it would be this ; see that the material is carefully
chosen and excellent in quality before it is given out,
remember most of all that the period of laboratory
belongs to the student for his work; when you do dem-
onstrate to a student let it be to show him that there
is much more in his material than he has been seeing,
that research involves careful observations and rea
ords as well az interpretation, and when yon leave him
be sure that he has a fresh impetus for his own work.

There is a double problem in, alL medical teaching;
medical schools are founded to train physicians, who
shall practice medicine, and research workers, who
shall advance medical science; that these two groups
are not entirely distinct all medical history attests.
I do not minimize the importance of training prac-
titioners of medicine, indeed in all schools they make
the larger group of the students, but it is entirely
clear that unless teachers of medicine attract and
train those who are to be teachers in the next genera-
tion, the profession will die at its source. Bnt, while
any given school will train only a small percentage


504                       HXENCE               [VOL. LXI, No. 1585

of its students to become professional investigators,
nevertheless all teaching in the sciences can and
should depend on the methods of research. All the
class can be taught in the spirit of research, which
means that it is more important for the student to be
able to find out something for himself than to mem-
orize what someone else bas said. Does any one doubt
that this principle applies to diagnosis'l Certainly in
the practice of medicine every case is a problem; and
therefore a plan of instruction for the practice of
medicine that allows great range for the idea of solv-
ing problems must be the ideal one. The knowledge
of what has been done must play a large r6le in the
training for any profession; nevertheless, the ability
to solve a problem is so much more difficult to acquire
than the ability to memorize facts that education
should stress the one even at the expense of the other.
Indeed the facts which one remembers from one's own
experience or from the experience of one's profession
are merely the tools with which to work

The ability to catch the imagination of young peo-
ple and direct their interests toward research is quite
a special gift in a teacher and each school must have
some members of its staff who enjoy this type of
teaching if that school is to contribute toward the
training of research workers. In the days when I
first started the study of medicine, the attitude to-
ward the research student was entirely different from
what it is now.  Then, from the student's standpoint,
it was unpopular to do research, and the one who
undertook it had little sympathy either from his home
or from his fellow-students. At present most of the
outside influences to be summed up under public
opinion favor research. Nevertheless, I believe that
the best method of getting students interested in re-
search is now the same as it was then, namely, through
an interest in ideas presented by a teacher who has
the power to catch the imagination of the gifted stu-
dent.  It may be that the student will apply for re-
search, it may be that the teacher will suggest a
problem to a student, but it is essential that student
and teacher shall be in sympathetic understanding.
The extent to which the student's mind will be turned
toward research is in direct relation to the quality
of intellectual leadership on the part of the teacher;
this quality is brought out both in lectures and in
informal discussions with students.  In connection
with lectures it is my fixed opinion that they should
be few in number and that they should not aim at
giving any comprehensive body of approved facts
such as are rightly set down in text-books, but they
should deal with the ideas in which the subject is
growing. A static subject needs no lectures.
In all the discussions concerning a comparative

analysis of the differences between European educa-

tional S@ASIS and outi, the point is brought out that
in Europe the student has much greater freedom of
choice and sequence of courses than we permit, and,
correlated with this freedom of choice, is his vastly
greater practice of wandering from one university t,~
another. In Europe the best students wander freely.
I can see great advantages in freedom of choice for
the student; in essence it enables him to choose h&
teacher. I should like to see a student able to try
medicine, then law or engineering on his own i&is-
tive, to find out what he really likes best without any
feeling of failure in his mind; nevertheless, I believe
that there is a point of far greater significance to
education than the discussion of freedom of choice
of a course and this point is freedom within the
course. I happen to know that one of the most
famous of the European wurses in histology wss con-
ducted in the following manner: the teacher sat in
the center of the room, with a slide and a microscope,
and his two hundred students sat around him, each
with a microscope and a section from the same block
and each student followed his section under the
microscope while the teacher described it. That is
drilling, not leading; that it gives thoroughness of
information and respect for authority, I do not
doubt, that it satisfies the average student, I grant.
I must say, also, that it gives an illustration, that
there is no one method of teaching, for it is true that
the nation in which large classes were taught in this
way has produced more investigators than we have
done. But the system was saved by the fact that
there were other factors in the community as a whole
that favored research, so that there were those whose
interest survived the system, and, when they under-
took research, they were then given the utmost free-
dom. Nevertheless, I' believe that the concept of
freedom for intellectual life on the part of the stn-
dent within the course is a far greater type of teach-
ing. Rules of how to teach can not be given, but
the negative side can be expressed, I do not believe
that a teacher gets the best out of students when he
presents scientific facts to them on the basis of his
own authority rather than as the shifting inferellces
from evidence. Why we think so, not just \yhat `\"
think, is the material of instruction.  There is no CM
method of teaching, but its essence is to lead thr
student to want to use his own mind. It is s n~`l'
more subtile thing than showing a student how to do
a physical exercise, but I believe that an entire clnss
should be taught in such a way that from the tefici'-
ing itself the abler ones will of their own initiaticc'
desire to do research. Teaching in a profession"
school I should regard as advanced, not elen=ntnr!.
instruction. Freedom within the course iuvzl$
much; it means eliminating quizzes, eliminatmm


MAP 15, 1925]                  SCIENCE

following of the student day by day to see if he has
done this task or that; the student's work will be his
own b&mss and will be done at his own initiative.
His note books and his records will be for his own
iustr&ion In a word, such freedom will mean treat-
ing the students of a class as you treat ~~earch S~U-
de& discussing ideas with them, suggesting plans of
,ork, putting your greater experience to his advan-
tage. In lieu of quizzes, a group of students could
often be advised to organize and to run small clubs
of their own in which they could look up and present
work exactly as they will do later in professional life.
If such a group had one or more members who were
doing research themselves and would present it to
their fellows, I should regard it as a great stimulus.
The proper teaching of a course would give many
suggestions of topics concerning which the students
would themselves desire further study.
Freedom within the course, then, I should offer aa
s major subject for discussion in education.  It is
dear, I think, that, in a laboratory course, we can
not mean, by freedom within the course, the utmost
liberty on the part of each student to select his own
material. Here he should be glad in the first place
to profit by the teacher's greater experience. More-
over, a research student can have a degree of freedom
with regard to material that is not feasible for a large
class. There are two drawbacks that prevent such
complete freedom for a class. The first of these is
the work and the expense of preparing the material
for a laboratory course. This is not true for the
sections for a course in histology; they are usually
cut in the summer months before the work is taken
and could be given out to the student at any time.
But it is true of the fresh, experimental material,
which must often be used at exact times after it has
been prepared and no laboratory can afEord enough
of the teacher's time or enough animals and materials
to allow the student to follow his own sequence.
Thus material in a laboratory forces the students to
work on the same general topic at the same time.
Secondly, no teacher is really equipped to lecture on
a subject without fresh study and fresh reading each
year. Everyone knows that we do not attempt to
remember all the details of our subject, we know that
one of the advantages for us in teaching is that each
year as we take up each subject in sequence we find
out what has been done in it, we study and think
about it and above all try to formulate whether we
can see some new opening to clarify it. Thus, from
the standpoint of material and from the standpoint
of the limitations of the teacher himself, it would be
difficult to offer to large classes of students the lib-
erty to choose the sequence of material to be studied
within a course, but, recognizing this limitation, how

much more important it is that he should have the
utmost intellectual freedom in studying the material.
It comes to this, then, that the liberty that is most
essential in education is intellectual liberty, freedom
of thought. Everything, else is secondary to this.
Dogmatism should be ruled out of teaching; the stu-
dent should be made to see that a book is merely a
record of what some one else has observed and thought
about the same material that is offered to him for
study and that the material itself is the safer guide.
You will assuredly have some difticulties if you dis-
cuss ideas of intellectual freedom with students; if
you tell them that it is more important to think than
to memorize, for they will have some very specific
experiences of examinations which were pure mem-
ory tests and for the most part they will discount
your sincerity.

One of Dr. Mall's most favorite sayings was that
an examination is more of a demonstration of a teaoh-
er's type of mind than a test of a student's ability.
To quote Miall's again, "An examination paper
should not be such that it could ,be handsomely an-
swered by a candidate who had free use of a text-
book. Papers of that sort are very common and
encourage the verbal memory too much." What shall
teachers do to counteract the reputation of their pro-
fession for dogmatism but to discuss liberty in edu-
cation in the freest possible way, especially with their
own students.

I wish now to discuss why I think that histology
has become such an important subject in medical re-
search. It is because histology has become the experi-
mental study of the living cell. When we seek to
trace this transformation in our subject we shall find
that many influences have brought it about, but in
evaluating the chief factors, I shall give first place
to the introduction of the method of tissue culture
by Professor Boss Q. Harrison  As we all know, Dr.
Harrison developed this technique for one purpose,
namely, to analyse the nature of those remarkable
processes that grow out from the cell body of the
neurone, but the method has ushered in a whole new
period in medical research. We, all know of the appli-
cation of this technique to mammalian tissues grown
in plasma by Dr. Montrose Burrows working in Dr.
Harrison's laboratory, of the further development of
the technique and of the results attained by Dr. Carrel
at the Rockefeller Institute, of the simpler technique
of Dr. and Mrs. Warren Lewis, by which tissues can
be grown in a fluid medium, which may not give as
high a percentage of growth as the plasma method
but which gives extraordinarily clear pictures of cells.
There are many other factors in the transformation
of this subject, the experimental embryology of Born,
the study of living eggs by the biologists, the early


506                       SCIENCE               [VOL. LXI, No. 1585

study of living lymphatics in the tadpoles' tail by
Dr. and Mrs. Clark, the study of living gland cells
by Dr. Bensley, the introduction of the so-called vital
staining by Qoldmaun, which hss assisted in the ex-
perimental analysis of phagocytosis, the technique of
supravital staining of cells and many other proced-
ures. All these investigations have made a new sub-
ject out of anatomy, but they have done something
much more important, they have broken down the
artificial barriers between the different medical sci-
ences. These things are not just the technique of
anatomy but rather of all those who use the micro-
scope.  In the premedical sciences we had separated
ourselves off into many groups for the purpose of
teaching, on account of the development of different
elaborate techniques; but we are now having a new
realignment in the medical sciences.  This realign-
ment is actually taking place through a natural evo-
lution in research; the type of problems which are
being analyzed at the present time are obviously much
more complex than those of a few years back,

Thus medical science itself is undergoing some such
transformation as I have tried to describe having
taken place within the one subject of histology.  The
great descriptive phase of medicine, when physicians
were concerned with the classification of diseases, is
drawing to a close; to-day we have as examples of
major problems the nature of immunity, the analysis
of how the cancer cell differs from the normal cell
and the fundamental analysis of nutrition.  It is
directly in relation to such general phases of medical
research, problems for research of interest to the
whole body of the medical profession, that it seems
to me that histology is playing a tile. It is because,
to use a specific example, one great phase of the sub-
ject of immunity is now specifically the experimental
physiology of the different types of the cells of the
connective tissues that the medical profession as a
whole can with profit come back to the most ancient
of its sciences, anatomy, for one of the newest of its
scientific techniques. In actual research at the pres-
ent time we have now in the premedical sciences not
six separate scientific branches, but three great groups
of workers, more or less distinct, on the basis of
technique, those who use predominately the micro-
scope, those who use the test tube and those who use
the kinograph as a symbol of instruments for meas-
uring mass action. Does not such a statement show
how the barriers have already been broken down be-
tween the premedical sciences?

In the great period of the specialization and isola-
tion of the sciences through which we have just passed
we have developed a great elaboration of nomen-
clature. So complex has scientific nomenclature be-
come that names rather than the actual complexity

of the subject serves to wall off a given science from
all other scientists. The complexity of nomenclature
will certainly be one of the factors of greatest difii-
culty in the organization of the new project of bio-
logical abstracts. We must, it is true, have some
specific names to be exact, but in the interests of the
whole body of scientific workers in biology could we
not insist that the titles of all papers should be so
simple that any educated person might be able to tell
what the paper is about, and the text so clear that
any scientist could understand itT This would not
involve giving up the exact terminology of science,
but it would involve giving simple synonyms; for
example, no anatomist can keep in mind all the names
of zoology, but he is immensely aided just to know
that carcinus is a crab. Let us get together on ideas
rather than separate on nomenclature.

If you compare the titles of scientific articles in the
journals of to-day with those of twenty years ago you
will find that we are beginning to work in groups,
often quite large groups. The nature of research is
changing in such a way ss to make this necessary.
If you will allow me to illustrate from my own ex-
perience, Dr. Cunningham, Dr. Doan and I have been
making some studies on the rhythms of the white
blood cells. We have taken an individual and made
studies of his blood every fifteen minutes all day long.
Every fifteen minutes we have made a total count
of the red cells, a total count of the white cells, a
differential count of the white cells by the vital tech-
nique, a wunt of the platelets and of the reticulated
red cells as well as a dMerentia1 count of the white
cells from fixed films. We have found that there is
an hourly rhythm of the white blood-cells, that every
individual covers the entire range of the normal num-
ber of cells per cubic millimeter, roughly, 5,000 to
10,000 cells each day, that the white cells are more
numerous in the afternoon than in the morning
whether the individual takes lunch or not, that the
neutrophilic leucocytes have an hourly rhythm and
die out in great showers in the circulation, that the
lymphocytes have a shorter rhythm and do not die in
the circulating blood to any appreciable extent and
that the variations of the number of the different
types of the cells are much greater than has been
suspected and yet the rhythms are remarkably con-
stant. It is quite obvious that such an experiment is
entirely impossible without joint research; without s
group of workers it would be left undone, in fact,
we had considerable help beyond our group of three.

This is an example of joint research in which al1
use the same technique, but we are also having joint
research between different groups. Perhaps one of
the most significant examples in modern medicine of
a joint attack on a major problem has been given us


MAY 15, 19251                  SCIENCE                        507
I -c
by the National Association for Tuberculosis in this  should never promise to remain so. Controversy is
country. A committee of that association has invited  entirely different in spirit from the stimulating dis-
h group of workers in the different fundamental sci-  cussions between different workers that are the real
euc.s to cooperate with them in an extensive study of  basis for the formation of scientific societies.  Herein
tuberculosis; and this committee is showing the most  lies a subtle difference in quality which may perhaps
far-sighted spirit of cooperation in putting the work  be expressed as follows: discussion stimulates while
of each division to the advantage of all the rest. It  controversy depresses.
might be a matter of interest to us as anatomists that   I offer then two topics for your consideration,
three of those who have been chosen for this work  liberty of thought in education and cooperation in
are members of this association.               research.
Another most interesting example of such a corre-                    FLORENCE R. SARIN
l&on is to be found emanating from the chemists    THF, JOHNS HOPKINS MJSDIOAL, SCHOOL
who have been studying rickets. The chemists have
obtained cooperation of both histologists and clini-
cians with the greatest possible advantage to the solu-
tion of their problem.  So many other examples
could be found in the various institutes for research
as to demonstrate quite conclusively that one of the
most striking features in the research of our time is
the development of cooperation.
The nature of joint research introduces a new fac-
tor to the problem of the training of students to be-
come investigators. In my judgment the most suc-
cessful method I f training students in research in the
past has been to start a student with a problem in
which he could work by himself, could make his own
specimens and analyze them; in joint research each
one has to be a cog in the wheel during the time of
the experiment; to put a student into such a group,
to let him work with you on the general problem is
really the time-honored method of the apprenticeship.
That an apprenticeship has worked well in the arts,
numerous examples of the student who has surpaSged
his master demonstrate, but I can not but feei that,
though the method must often be accepted on account
of the necessities of our problems, it calls for extra
safeguards lest the student become a mere technical
assistant and get no start in independent work him-
self.
There may be, of course there will he, personal
dif&ulties in joint research, but certainly they will
be no worse than our old scientific controversies. I
have had some experience with scientific controvvy,
and in my judgment it is a poor technique.  The
flaw in it is this, that in controversy one seeks to oon-
vince one's opponent by argum?nt and evidence that
one's own theory is right and his theory is wrong.
Now this is the exact thing that is not worth doing;
because ss long as a subject is growing, or in Iorder
that it may grow, it is of the utmost importance that
people should be working on difTerent theories. The
worst effect of controversy is on the individual who
takes part in it, because it tends to force him into
contracting a marriage with his own theories; assur-
edly he should be in love with his theories, but he