FEDERALSECURITY AGENCY U.S. PUBLIC HEALTH SERVICE IN REPLYING. ADDRESS THE Tbc. &search Laboratory, l+ll E, 69th Sto, New York 21, N. Y, September 12, 1949. Dr. Joshua Lederberg, Department of Genetics, UniversJ.ty of Wisconsin, College of Agriculture, Madison 6, Wisconsin. Dear Josh: Thanks for sending me culture W-1104 which we will try to get into the works soon0 I just got back from California today and will be sending you within a few days some double and triple mutants of the Waksman strain* You will reoall that we could not get these mutants to combine with your K-l.2 multiple mutantso I am awfully glad you enjoyed having Gordon Allen in your lab and I want to thank you again for all the trouble you took to help get him started. I haven't yet seen him so I don't know the present status of the meningococcus problem, but I understand it was set back quite a bit when the incubator overheated last week. Luria has given me your article on "Methods of Isolation11 for comment, with the suggestion that any e,tiensive additions might go in as footnotes. I hope you won't mind my taking the liberty of making a number of minor suggestions oRyour material, as well as adding some of our own. I should think this would be a very useful kind of publication0 I note that you refer in this to an optimal concentration range of vitamin B-12, I wonder whether this is based on the requirements of other organisms, or on a mutant of E. coli? -- During the summer a mutant requiring R-12 was isolated here several Q-I the way back from Pacific Grove I stopped at Pasadena and made tentative arrangemnts about a course to be given there next summer* I mentioned to Delbruek and Beadle that you had once said you would be glad to cooperate in such a course, especially if given in California. I hope you still feel the same way, for it would be a lot of fun if we could all get together. By now you have probably heard from Beadle. So far I have made only a very rough outline of a three-week course modeled on the bacteriophage course* -2- Dr. Joshua Lederberg September 12, 19490 The best general plan seems to be to spend about one week on techniques of isolating mutants, one week on biochemical tricks such as we have emphasized in this lab, and one week on recom- bination. Max has suggested that it would probably be best to have one parson responsible for the course rather than have people take turns, in which case I would presumably take the first &wo weeks and you the third. I do feel, however, that a fair amount of the material of the first week, such as delayed enrichment techniques and fermentation mutants, is material which you have developed and could therefore di.scuss more authoritatively than I could0 When I get a more detailed outlj.ne I am sgre we will be able to work out a satisfactory division of labor. I naturally would welcome any suggestions you would have on the organization of the first part of the course, and will send you the outline at a later date. The big question is where and when the course should be given. Max is anxious to have it in June immediately after the end of the term, since he and Manny would like to spend the rest of the summer in Cold Spring Harbor. Beadle has suggested, however, that the Corona Del Mar lab would be vacant in August and he would like very much to outfit it so that work of this sort could be carried out in order to give the place a new lease on life. It is my feeling that June is a pretty good month to stay in New York, and I would much prefer to give the course either -In Pasadena in July or Corona Del Mar in August. If we put up a united front perhaps we can persuade Max that if he is going to make his lab the center of bacterial genetics next sUmmer, the price might have to be giving up Cold Spring Harbor. I cannot easily put up aw absolute refusal since I have no fixed schedule to keep me here. I look forward to hearing from you, especially about the course. Best regards to Esther, Sincerely, Bernard D. Davis, Senior Surgeon. BDD/hl P.S*- We have had no difficulty in obtaining a trtple mutant from one requiring PABA a a proline, usi.ng the Waksman strain and the penicillin method. since *success would not have been expected on the basis of your results with proline requiring mutants, I wonder if you would mind sending us one or more of your proline requiring mutants. As you remarked last winter, this is perhaps the sort of lead I should not over- look in connection with chemotherapy,