ANIMAL PRODUCTION. 465 



the heat output was somewhat greater, and for heavy infants a little less 

 than the average metabolism of 2i calories per hour per kilogram of body 

 weight. 



ANIMAL PRODTJCTIOK 



Nutrition with purified food substances, E. V. McCollum and Marguerite 

 Davis (Jour. Biol. Chan., 20 {1915), No. Jf, pp. 641-658, figs. 5).— In continua- 

 tion of previous w^ork (E. S. R., 32, p. 3G0), the authors report results of addi- 

 tional fee<ling experiments. 



Laboratory animals (rats) were maintained upon a basal ration of pure 

 casein, dextrin, lactose, agar-agar, and chemically pure salt, to which were 

 added different food materials. The basal diet was incomplete, the rats showing 

 normal growth for a period of about 6 months and then rapidly losing weight. 

 The addition of olive oil to the basal ration did not prolong the growth period, 

 as did the addition of butter fat or the ether extract of cod testicle or pig kidney. 

 When maintained upon a diet to which butter had been added, rats gave birth 

 to young, some of which were maintaiuetl for a long period of time on the same 

 diet as the mother. The results of feeding experiments by Osborne and JMendel 

 (E. S. R., 31, p. 560) are discussed in relation to the results obtained by the 

 authors. 



The influence of certain vegetable fats on growth, E. V. McCJollxjm and 

 Marguerite Davis (Jour. Biol. Chem., 21 {1915), No. 1, pp. 179-182, pis. 9).— 

 In continuation of the work reviewed above, exi^eriments are reported in which 

 laboratory animals (rats) were maintained upon a fat-free diet of casein, milk 

 sugar, dextrin, agar-agar, and pure salt until a loss of weight and enfeebled con- 

 dition of the animals resulted. Fifty per cent of this fat-free diet was then 

 replaced by various vegetable substances containing fat, such as corn, wheat 

 embryo, rye, and rolled oats, and in some experiments by dried pig heart and 

 kidney. 



When the corn or wheat embryo was added to the diet the animals showed an 

 increase in weight and a normal appearance. Less favorable results v\'ere ob- 

 tained by the addition of the same amount of the entire wheat kernel, rye, or 

 rolled oats to the diet. 



The results of these experiments showed that " 50 per cent of corn added to 

 the fat-free diet is vastly superior to 5 per cent butter fat when the animals 

 have been brought to a point near which failure of nutrition would set in. 

 The addition of 5 per cent wheat or 5 per cent corn meal is not sufficient to 

 prevent decline and death on the fat-free diet." 



The authors state that " the effects of wheat, rye, and oats seem to suggest 

 that the differences observed in their effects on depleted animals may well be 

 due to quantitive differences in the yield of the unknown accessory substances 

 under consideration rather than to an entire absence of the same. This view- 

 point is strongly supported in the case of the wheat kernel as compared with 

 wheat embryo." 



The value of the proteins of the cereal grains and of milk for growth in 

 the pig, and the influence of the plane of protein intake on growth, E. V. 

 McCoLLUM {Jour. Biol. Chem., 19 {1914), No. 3, pp. 323-333). — In metabolism 

 experiments with young pigs fed on rations made up of purified feedstuffs, the 

 principal sources of protein being oats, wheat, corn, wheat gluten, casein, and 

 skim milk, supplied at different planes, it was found that " with moderately 

 low protein intake (6.6 to 10 per cent) the rate of nitrogen retention is in- 

 fluenced by the amount of food protein in proportion to the metabolizing tissues 

 of the body and apparently in some degree by the excess of total energy con- 

 sumed over the maintenance needs of the animal. When the energy supply is 



