DEPARTMENT OF EXPERIMENTAL EVOLUTION.* 



C. B. Davenport, Director. 



The work of the Station for Experimental Evolution has during 

 1919 emerged from its war status of comparative quiescence in its 

 strict work to one of renewed activity. Many of the staff who have 

 returned from army service are doing so with keener zest for the work 

 that they regretfully laid aside and a resolution to bring to fruition 

 many matters that had been long developing. On the other hand, 

 the expense and waste of war still have their effect, and will for years 

 to come, upon the cost of carrying on scientific work. 



Among the principal advances of the year have been : 



(1) The completion of the evidence that the offspring of alcoholized 

 rats, to the second generation, are less capable of learning than the 

 controls. This suggests an alteration of the germ-plasm by alcohol. 



(2) The evidence of a certain amount of testicular degeneration in 

 consequence of the use of alcohol. 



(3) Further evidence, by the method of correlation, of the inefficiency 

 of "selection" after the gametic factorial composition has been simpli- 

 fied in the earliest generations. 



(4) Evidence that "staleness" of sperm does not influence the sex- 

 ratio in pigeons. 



(5) Statistical demonstration of the great increase in the proportion 

 of males born from "hybrid" as opposed to "pure" matings in man. 



(6) Statistical evidence that more still-births occur in "pure" than 

 in "hybrid" matings; and that in "pure" matings there are relatively 

 more males in first-born children than in later births. 



(7) The discovery that species of Portulaca, like some other plant 

 species, break up into numerous biotypes, including a dwarf form, 

 and that they show abundant bud mutations. 



(8) The dwarf Portulaca is a Mendelian recessive ; so too is the weep- 

 ing character of a mulberry tree as opposed to the erect form. 



(9) The demonstration of four factors for color in dogs, one occur- 

 ring in a triple allelomorph series. 



(10) A demonstration of the chemical lack of differentiation in the 

 brains of ataxic pigeons. 



(11) Demonstration of the law of osmotic concentration of phanero- 

 gamic epiphytes as compared with their hosts. 



(12) The determination of correlations between age, weight, and 

 pulse-rate and body surfaces, on the one hand, with each other, and, 

 on the other hand, with heat production and gaseous exchange, for 

 men, women, and children. 



(13) Statistical demonstration of the non-validity or insufficiency 

 of the body-surface law of human basal metabolism. 



* Situated at Cold Spring Harbor, Long Island, New York 



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