470 EXPERIMENT STATION EECOliD. 



minimum amount of food proteid requisite for tlie production of a definite 

 quantity of millv. With a ration rich in carbohydrates and a supply of niti-o- 

 genous materials only equal to the total amount in the excretory products and 

 in the milk, the cows continued for a long time to give a considerable quantity 

 of milk of good composition, almost the whole quantity of digestible protein in 

 excess of their maintenance requirements appearing in the milk. The author 

 believes that though the results obtained indicate that milk-giving animals nijjy 

 be made to be especially economical of the protein in the ration, they do not 

 warrant the use of such small quantities of protein in feeding. 



Some attention is also paid to results obtained in experiments on the substi- 

 tution of ammonium acetate for part of the digestible protein in the rations. 

 With an abundance of carbohydrates in the ration the ammonium salt seemed to 

 be able to take tlie place of some of the food proteid in milk production. The 

 author suggests that it was " api)arently converted into proteid in the chyme," 

 perhaps tlirough the influence of bacteria. 



The effect of rations rich, and poor in fat on milch cows iLandw. Jahrb., 

 36 (1907), Xo. -'/, pp. 72-'i-7S8). — In 3 corresp»mding feeding periods the rations 

 contained 2.77 kg. of digestible protein and 12.120 kg. of digestible nitrogen-free 

 substances per 1,000 lbs. of live weight, but in the first and third periods the 

 quantity of fat was only 0.64 kg., whereas in the second it was 1.17 kg. The 

 quantities of milk and fat produced daily by each of the 15 cows on these rations 

 are given. From the results obtained, the conclusion is drawn that the effect of 

 the one ration is the same as that of the other. 



The effect of emulsified and nonemulsified food fat upon milk production, 

 C. Beger {Landw. Vers. Stat., 67 (1907), No. 1-2, pp. 1-25).— In continuation of 

 previous work (B. S. R., IS, p. 171), the author fed 3 goats with whole milk as 

 a typical emulsified fat, and with skim milk and melted bi^fter fat as a source of 

 nonemulsified fat. From the results of the experiments the conclusion was 

 drawn that the fat as an emulsion in the form of whole milk had the greater 

 influence upon the milk secretion. The effect upon the body weight of the 

 animals was so small and so variable that no conclusion regarding it could 

 be drawn. 



Should concentrated feeds be fed wet or dry? Leithiger {Sachs. Landw. 

 Ztschr., 55 (1907), No. 25, pp. 693-695). — From the better milk production and 

 gain in body weight obtained in experiments with S cows fed their concentrates 

 for one period wet and for another dry, the author concludes that it is more de- 

 sirable to feed concentrates dry. 



On the histology of the milk glands of the cow, P. Lenfers (Ztschr. 

 Flcisch u. MilchhiKj., 17 (1907), Nos. 10, pp. 3 ',0-350 ; 11. pp. 383-390; 12, pp. 

 ^24-H9)^ — In these investigations, the author used tissues from the milk glands 

 of cows of different ages, at difl'erent periods during pregnancy, at different 

 stages in the lactation period, and of cows dry for different lengths of time. 

 He describes his method of preparing the tissues Sor microscopical exam- 

 ination, and discusses his data with special regard to the condition of the 

 milk glands before the birth of the first calf, during lactation, and during invo- 

 lution, comparing his own conclusions with the opinions of previous investi- 

 gators. A bibliography is appended to the article. 



Contribution to the knowledge of the composition of the fat of cow's milk, 

 W. Fleischmann and H. Warmrold (Ztschr. Biol., 50 (1907), No. 3, pp. 375- 

 392). — As reckoned from the quantities of glycerin and volatile and nonvola- 

 tile fatty acids determined in 4 samples of milk fat, the elementary composition 

 of the fat averaged 75.25 per cent carbon. ll.SO per cent hydrogen, and 12.81) 

 pel' cent oxygen. In the average of 26 analyses of 9 samples of lactic acid-free 



