DEPARTMENT OF EXPERIMENTAL EVOLUTION.* 



C. B. Davenport, Director. 



Among the principal advances of the year have been: 



(1) The demonstration of the paralleUsm of the mutations in related 

 species of the fruit-fly, Drosophila, and further evidence for the con- 

 clusion that the factors for them occupy corresponding places in the 

 chromosomes. 



(2) The discovery of a set of conditions of the environment which 

 induces the appearance of males in a parthenogenetic species of ento- 

 mostraca. 



(3) The demonstration of the great effect of inhalation of alcohol on 

 the growth and fecundity of rats. 



i4) The acquisition of additional evidence that the gradual change in 

 the somas of a population by selection of parents may be due merely 

 to the isolation of individual factors out of many concerned with the 

 same trait. 



(5) The analysis of a new method of selecting the best egg-laying 

 birds in a flock of poultry. 



(6) The discovery of a form which acts much like a dominant 

 mutant in jimson weed but which seems to depend on a parasite for 

 its production. 



(7) The production of a ''pure" highly abnormal race of beans. 



(8) The analysis of the juvenile traits and hereditary characteris- 

 tics of successful naval men. 



(9) The discovery of a method of forcing pigmentation in albinos. 



(10) The discovery of an extraordinary variability in sap concentra- 

 tion in plants, which throws Hght on the rise of sap in trees, on the 

 acquisition of food from their hosts by parasitic phanerogams, and on 

 the relation of sap properties to the solutions in the substratum. 



(11) The origination of mutations that are sterile with the parent 

 species. 



(12) The completion for press of the unpublished scientific work of 

 Professor Charles 0. Whitman. 



STAFF. 



The work of this Department during the present year has been car- 

 ried on by seven resident investigators and various associates and 

 assistants. In addition to his administrative duties the Director has 

 prepared for pubUcation a work on naval officers, their juvenile traits 

 and family history. As a member of the Anthropological Committee 



♦Situated at Cold Spring Harbor, Long Island, New York. 



Ill 



