1917] ANIMAL PRODUCTION. 773 



attempt was made to determine, by isolation and chemical analysis of the yolks 

 of eggs subjected to various periods of incubation, the relative rates at which the 

 various constituents of yolk are removed and utilized by the embryo. 



A differential utilization of the elements of yolk prior to the twelfth day of 

 Incubation has not been shown to occur. A study of the unmetabolized yolk of 

 12, 18, and 20 day stages shows that after the twelfth day the phosphatids are 

 utilized more rapidly than the neutral fats, and the neutral fats are utilized 

 faster than the proteins. This order of utilization of these substances persists 

 during tlie 18 to 20 day period when the embryo's sole source of protein is thv» 

 protein of the yolk. The moisture value of the yolk undergoes very considerable 

 fluctuations during incubation. At the twelfth day it is about 9 per cent higher 

 than in fresh undiluted yolk. At the eighteenth day it has fallen to near the 

 value for fresh yolk. At the very end of incubation this value probably rises 

 considerably. Two forms of semisolid yolk bodies which are occasionally present 

 in final stages of incubation were found to be wholly unlike in their chemical 

 composition. Yolk resorbed by the follicle which secreted it shows a more rapid 

 utilization of the phosphatids (lecithin), the neutral fats are utilized at a some- 

 what slower rate, while the proteins are metabolized more slowly than either 

 the pho.sphatids or neutral fats. 



IV. WJien a gland functions for the first time is its secretion the equivalent 

 of subsequent secretions? O. Riddle and Adelaide A. Spohn. — A comparison was 

 made of the composition of the albumin secreted by the pigeon's oviducal glands 

 in their Initial functionings with that of albumin secreted later by these glands. 



Albumin produced in initial efforts contains a smaller percentage of water and 

 a higher percentage of alcohol-ether-insoluble substance. During a few of the 

 earlier functionings of the oviducal glands, there probably occurs a gradual 

 change from the initial lower percentage of water to the later higher percentage 

 of water. Partial analyses of the albumin of the pigeon's egg are recorded and 

 one source of variation in the moisture value of this albumin has been identi- 

 fied. The amounts of alcohol-ether-soluble substance, and of inorganic matter 

 probably do not vary widely nor consistently. The amount of water in the egg 

 albumin of the pigeons studied shows no consistent variation in respect to sum- 

 mer and winter. The earliest secretion of the albumin-secreting gland of the 

 pigeon's oviduct is, in several respects, a rather clo.se approximation to the later 

 products of the gland. 



V. The effect of alcohol on the size of the yolk of pigeon's egg, O. Riddle and 

 G. C. Basset. — In the studies here reported two common pigeons, two blond Ring 

 doves, and three hybrids were used. Four of the birds were given alcohol by 

 inhalation daily, with certain exceptions, for four months, and three for only 

 two months. It was found that the yolks produced during the alcoholization 

 period by these birds become smaller than during the prealcoholizatlon period. 

 This decrease occurs even during the season when the yolks of untreated birds 

 normally grow larger than in the earlier period. Yolks produced during a few 

 weeks or months after the alcoholization period are smaller than normal. 



VI. Sexual differences im, the fat and phosphorous content of the blood of fowls, 

 J. V. I>awrence and O. Riddle. — Re.snlts are given of a .study of the amount of 

 fat and phosphorus in the blood, in relation to sex and sexual activity, in the 

 common fowl. 



The blood plasma of female fowls is found to be richer In alcohol-solxible sub- 

 stance and phosphorus than is the plasma of the male. The blood plasma of the 

 sexually functioning female fowl contain.s more alcohol-soluble substance and 

 more phosphorus than does the plasma of fowls with temporarily Inactive ovary. 

 The male, the nonlaylng female, and the actively laying female fowl are three 

 natural groups of fowls when these are considered from the standpoint of the 



