DEPARTMENT OF EXPERIMENTAL EVOLUTION. 141 



transplantation work and to gain information as to the nature and 

 effects of tumor growth. 



During the summer, Dr. George B. Jenkins, of the Department of 

 Embryology, Carnegie Institution of Washington, made preliminary 

 studies of rumplessness, polydactylism, and abnormal plumage of 

 Rumpless and Silky strains of poultry at this Station. 



EXPERIMENTAL PRODUCTION OF VARIATIONS. 

 EFFECT OF CAVE CONDITIONS. 



The experiment of comparing the effect of cave forms reared in the 

 light and epigeal forms reared in caves, with the corresponding vari- 

 ations of these in their original habitat, is being continued by Dr. 

 A. M. Banta. During the year he made successful collections in caves 

 in the middle West, and we have now more cave material than at any 

 previous time. The amount of material of most of the more readily 

 breeding species is satisfactorily large. 



PHYSIOLOGY OF REPRODUCTION. 

 BIOMETRIC STUDIES OF EGG PRODUCTION. 



Dr. Harris has continued his statistical investigations into the phy- 

 siology of egg production, with special reference to the prediction of 

 egg production from short periods of observation. These are made 

 in cooperation with three of the agricultural experiment stations. 



OTHER INVESTIGATIONS. 

 CONTROL OF PROTEIN PRODUCTION IN EGG-WHITE BY QUININE. 



Riddle and Anderson had already shown that the amount of the 

 nitrogen-containing substance (protein) in egg-white was reduced under 

 quinine. It remained to determine whether the reduction in weight 

 implied also an actual and absolute reduction in nitrogen, or whether 

 the reduction occurred in non-nitrogenous associates of the protein. 

 This work was chiefly carried on during the past year by Dr. Ellinor 

 H. Behre. An actual reduction of the nitrogen element has been found. 

 This work has now been brought to a termination by Drs. Riddle and 

 Behre. Their conclusions are as follows: 



"Fresh-laid dove eggs contain about 12 per cent nitrogen per gram of solids. 



"The data of Riddle and Anderson on the reduction of egg size and yolk 

 size under quinine treatment are further corroborated by the records of 6 of 

 7 birds retested — egg size and yolk size are decreased during dosage and 

 increased after dosage is discontinued. 



"The normal quantity of (a more dilute) albumen is restored quickly after 

 discontinuance of dosage. 



"Less albumen is produced during dosage than before. Relatively more 

 (of a more dilute) albumen is produced after dosage is discontinued than 

 during dosage. 



