774 EXPERIMENT STATION RECORD. [Vol. 37 



fat and phosphorus content of the blood-plasma. The relative distribution of 

 phosphorus in the alcohol-soluble and alcohol-insoluble fractions of the bluo<l 

 plasma is also different for these three groups of fowls. The differences here 

 observed and measured are quantitativa 



VII. Variations in the chemical composition of reproductive tissues in rela- 

 tion to variations in functional actimty, O. Riddle and J. V. Lawrence. — 

 The membranes which immediately surround different sizes of growing oocytes 

 of the fowl were analyzed. The phosphatids of all the membranes analyzed 

 were found to exist in amounts relatively large in proportion to the neutral 

 fats. The greatest disproportion of phosphatids to neutral fats, and the 

 largest amounts of pho.sphatids, apparently were found in the membranes sur 

 rounding oocytes from 5 to 6.5 mm. in diameter. 



Analyses were also made of active and relatively inactive shell glands 

 and albumin-secreting glands. In the shell gland.s the total alcoliol-ether 

 soluble substance is greatest when the gland is inactive and the moisture is 

 greatest when the gland is active. While the alcohol-ether soluble phosphorus 

 does not differ consistently in the active and inactive shell glands, it is per- 

 haps higher in the active glands. In the albumin-secreting glands the alcohol- 

 ether soluble phosphorus is much increased under inactivity. The percentage 

 of water is somewhat larger in the active than in the inactive albumin- 

 secreting glands. 



The results are thought to indicate that an increase in the physiological 

 activity of a tissue is accompanied by an increase in its phosphatid content. 



A study of the incubation periods of birds, W. H. Bergtold (Deni'er: The 

 Kendrick-BeUamy Co., 1917, pp. 109). — The author reviews the reasons assigned 

 for the variations in the incubation periods of birds which are based on 

 passive conditions, such as an anatomical character (size of body), a histologic 

 character (size of egg), and effects which merely retard or suspend embryonic 

 development. 



Attention is also called to a fs'.ctor that has received little attention, namely, 

 bird temperatures. The importance of a study of bird temperatures is urged 

 because it has been demonstrntofl that there is an optimum incubation tempera- 

 ture, which perhaps varies with different species. He puts forth the tentative 

 conclusion that " a bird's temperature determines or fixes the time length 

 of its incubation period, and that only an abiding change in the bird's tempera- 

 ture can permanently alter the time length of its incubation period." 



The molting of fowls, R. F. Ibvin {New Jersey Stas. Hints to Poultrymen, 

 5 (1917), No. 10, pp. J/). — A discussion of the molting of fowls from which the 

 conclusion is drawn that it is better to food the Inrds liberally during the 

 period, and that no gain is made in forring the molt by starving. 



Protein feeds for laying hens. H. L. IvEkcpsTFiR {Missouri Sta. Circ. 82 

 {1917). pp. 11. figs. 4). — In continuation of work already noted (E. S. R.. 3o. 

 p. 77.3) three 10-blrd pons of White Leghorn hens were fed from November 1, 

 1915, to October 31, 1916, to test the effect of sour milk on egg protluction. The 

 rations of the different pens were identical with those of the previous yo.ir. 

 Tlie average number of eggs per hen laid by the no-raeat-or-milk pen during 

 the year was 59.7, by the beef-scrap fed pens 133.6, and by the sour milk fed 

 hens 126.9. On the price basis of the previous year there was a loss of 5 cts. 

 per hen on the no-meat ration, a profit of .$1.04 per hen on the beef-scrap ration, 

 and a profit of 92.4 cts. per hen on the sour-milk ratio. 



In another te.st covering the same period linseed meal, gluten meal, and 

 cottonseed meal were compared as sources of protein for laying hens. In this 

 test, which involved three pens of 10 White Leghorn hens each, the birds wer<' 

 fed a mash composed of equal parts by weight of bran, shorts, corn meal, and 



