DEPARTMENT OF EXPERIMENTAL EVOLUTION.* 



C. B. Davenport, Director. 



The principal advances of the year have been in demonstrating a 

 chemical basis for sex-differentiation, a subject to which we have 

 paid special attention during the past few years; in opening up new 

 types of inheritance-behavior in the Oenotheras; in completing the 

 demonstration of duplicate determiners for a single character in 

 Bursa; in discovering the first case of sex-limited heredity in plants; 

 in demonstrating the method of inheritance, in man, of tendency 

 to periodic "fits" of temper and certain other elements of the hys- 

 teria-complex. 



STAFF. 



The Director divided his time for research between breeding exper- 

 iments with poultry, canaries, sheep, goats, and cats, and the study 

 of data secured by trained field workers on certain points in human 

 heredity. On the occasion of attending a meeting of the American 

 Breeders' Association at Columbia, South Carolina, he was able to 

 make additional studies on the heredity of skin pigmentation in 

 negro-white crosses, the results of which are incorporated in a memoir 

 on this subject about to appear as Publication No. 188. Dr. G. H. 

 Shull has found that the time demanded for his experimental work 

 has prevented him from completing the Burbank manuscripts and 

 it has been arranged that he shall devote a season to the completion 

 of that manuscript. He will probably be absent from the Station 

 for twelve months. Dr. Shull's green-house assistant, Mr. Leo 

 Macy, is to be given leave of absence for further study, and Mr. C. W. 

 Crane, who has been in training during the present year, will take 

 his place. During this summer, Dr. G. H. Shull also was assisted 

 in his fertihzations and records by Mr. William F. Friedman. Dr. 

 J. A. Harris was absent during several months of the winter work- 

 ing at the Desert Laboratory. Meanwhile, his three assistants and 

 computers were preparing data from the harvest of the preceding 

 season. His work is largely of a statistical nature and has included 

 the rearing and observation of scores of thousands of seedlings. Dr. 

 R. A. Gortner has had charge of the biochemical laboratory, and 

 besides continuing his studies in melanin has cooperated in various 

 researches with Doctors Banta, Blakeslee, and Harris. Dr. A. M. 

 Banta has had charge of the experiments with the cave organisms 

 and has made other studies on the relation of organisms to light, 

 notably the production, by selection, of races that differ in responsive- 



♦Situated at Cold Spring Harbor, Long Island, N. Y. Grant No. 860. $91,854 for 

 investigations, maintenance, and construction during 1913. (For previous reports see 

 Year Books Nos. 3-11.) 



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