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Dr. Maxine Singer
Department of Health ,
Education and Welfare,
National Institutes of Health
Bethesdg, Md. 20014
Room 9N-119, Bldg. 10

Dear Maxine. and Dan,

If I were to rank my debts to the Singer's family in a chro-
nological order I should first address my apologies to you Dan,
but I hope you will not mind if I addrc'ess'the lady first.

Maxine, thank you so much for your letter and comments  on our
manuscript. I agree with your opinions and evaluation of the work.
There is a lot to be done to make it a completed entity. Of course,
further characterisation of the hands displaying the most intere-
sting developmental behaviour is basic, but I am not sure, whether
the other two points merit the priority instead.  First: analysis of

@IY,the dynamic aspects of the synthesis of the proteins separated in
' tlp'pb our electropherograms by use of labeled precursors. In this way one
bta4w  will get better understanding on the immediacy of the events pictu-

red in changing electrophoretic patterns.  Second:  would not it be
reasonable before attempting elaborate characterization to see how
                                            and select

the most interesting one among them for subsequent work. You recall
our talk about that possibility on Spetsai.

do the protein patterns in human organogenesis change,

As far as protein characterization goes we hope to be able to
do the subcellular localization of the protein by differential cen-
trifugation, or by autoradibgraphy; protein separation by gel fil-
tration, ion exchange chzomatography, disc electrophoresis, and gel
electrofbcfiaihg; ,and at the most the approximate molecular weight
determination by Sephadex gel filtration. Characterization beyond
that level is completely out of our reach. Even the outline of the
techniques mentioned will be realized with appreciable efforts.

Of course all that work is on my program only after I finish
writing my Ph. D. thesis. So in the present phase of exhausting
but unproductive work, I was really discouraged with the cited
criticism /J.Embryol. exp. Morph./ and I am thankful to you for
the encouragement. I appreciate your effort so much more since you
were also in the period of writing. By the way, I would be greatly
honoured by being included in your.mailing list for reprints of your
works.
Now, Dan I am awfully sorry for mixing your letter of August 8,
containing the information on optical prescription mounting in masks,
among some of my papers, and finding it only very cecently. Thank
you for it so much and please forgive my neglecting it so far. I am
forwarding the information to the cousin of mine who was doing so
far his own home made improvisations.

Thank you also for the lovely photographs which revive pleasant
memories of the good old times. Earnaio and guitars, ouzo and octo-
podi, all that sun and the sea of the Spetsai. By the way, Maxine,
do you recall our evening ouzo and octopus at the water front / it
was the first evening together upon Dan's arrival/ when we discussed

dr. Crick's rough time answer on my question concerning dr. Orgel's
statement that prcteins might have influenced informationcontent
ofsin geologic p.ast? You were not happy with it and neither
was I. But I have come accross a nice little paragraph titled
"Inactivity of new genetic material  in Britten and Davidson's
paper /Science 165: 356/ which says in another words exactly the
content of my question. I feel a little bit happier now, the
question af&;er all was not that stupid ! The very same theory
might provide a plausible answer to my second question answered
at the tine by dr. Orgel, that definitely and neatly eliminates
need for architectural and particularly temporal genes.

Well to finish recollection of the pleasant and the less
pleasant memories, in my private life we are busy furnishing the
new flat we were given by the pharmaceutical works where my wife
works. After six years of living with my father and mother in
law we are making final arrangements to move away.

How-is my friend Ellen doing these days? Ellen are you busy
taking care of all the members of your little comunity ? I have
only two to look after and it keeps me fairly busy. You recall
mentioning my daughter Karin /T years/ and son Alan:/3 years/
and they are extending to you their very best greetings. 1 shall
send you a photograph of them, and I hope you will remind your
parents to find one of all of you, for us. Thank you Ellen, you
know we would like to have one very much.

With our very best regards,

Yours,