DEPARTMENT OF EXPERIMENTAL EVOLUTION. 105 



issued during the calendar year. The proofs of volume ii of the same series 

 of books has been carried through two galleys with the aid of Dr, Banta. 



"Throughout the entire year Dr. Riddle's chief effort has been directed to 

 the assembling of a complete account of his past seven years' study of sex in 

 pigeons. Although this work has been carried on with the utmost speed, it 

 was not possible to make the book ready for publication before his entrance 

 into war service. Nearly 700 tables of data have been completed, seriated, 

 and numbered. The outline of the entire book is complete, though a few 

 tables of data and a textual exposition of the results are still wanting. In 

 this account work with the common pigeons has been almost entirely omitted. 

 The previous experience of his assistant. Miss Holmes, will, however, enable 

 her nearly to complete similar tabulations for that large body of data, probably 

 during the next six months. 



"Three new studies have been undertaken during the present year : 



"(a) The effects of quinine on the production of egg yolk and egg albumen 

 in the pigeon. This study, carried out in collaboration with Mr. Carl E. 

 Anderson, has shown that the knowoi nitrogen-conserving action of quinine 

 extends to the production of the two above-mentioned substances. Relatively 

 less egg albumen, and yolks of smaller size, result from dosage (1 grain daily) 

 with quinine. In this case the smaller size of the yolks (ova) is probably 

 induced by an effect upon the nitrogen metabolism rather than upon the 

 general metabolism, and effects upon the production of sex from these treated 

 germs are possibly not to be expected. Because of the previously observed 

 relation of the general metabolism to sex the data for the sexes which arise 

 from these treated germs is being carefully studied. 



"(b) The effects of urotropin on the size and developmental capacities — 

 with particular reference to sex — have now been studied during several 

 months and the work is still being continued. It is known that this compound 

 breaks up in the tissues into ammonia and formaldehyde. We have demon- 

 strated that urotropin is absorbed by the ovum. This drug, therefore, offers 

 the possibihty of affecting the general metabolism of the egg-cell during its 

 entire growth period. The results should be reported later when both the 

 data for yolk size and for sex are complete. 



"(c) The chemical composition of the brains of ataxic (?) pigeons is being 

 studied in collaboration with Miss Mathilda L. Koch, of the Psychiatric 

 Institute of the New York State Hospitals. The first appearance of this 

 disorder of the voluntary movements (in an individual hatched from a 

 weakened germ) and the transmissibility of the character to the fourth genera- 

 tion have been reported in the Year Books of previous years. The results 

 of our first chemical study of these brains indicate that the brains of affected 

 individuals are chemically under-differentiated, i. e., juvenile or infantile in 

 comparison with brains of normal individuals of the same age and strain. 

 This material offers the greatest advantages for a study of the chemical 

 aspects of hereditary mental disease, and a further study is in progress. 



"In addition to these new lines of study nearly all of the several lines of 

 investigation conducted by us during the past seven years on the nature and 

 reversibility of sex have been continued. These results again confirm our 

 earlier conclusions. They have, in greater part, been incorporated into the 

 summary of our completed studies on sex. 



"Mr. Karl E. Anderson assisted our general work until May 1, 1918. He 

 collaborated in a study of the effects of quinine on certain aspects of the 

 physiology of reproduction in doves and pigeons. Mr. Anderson joined the 

 Army on May 1. His present duties are with the Sanitary Corps. 



