160 EXPEEIMENT STATION EECOBO. [Vol. 36 



Studies on growth. — III, The comparative value of lard and butter fat in 

 growth, C. Funk and A. B. Macallum (Jour. Biol. Chem., 27 {1916), No. 1, pp. 

 51-62, figs. 2). — The experiments reported in this paper were carried out to 

 determine the relative value of lai'd and butter fat as the fat fraction of the 

 artificial diets studied in previous work in this series (E. S. R., 34, p. 561). 



If laboratory animals (rats) wei"e maintained on a diet containing dried, 

 powdered yeast and lard as the fat component, they grew normally for from 

 60 to 90 days but eventually displayed scorbutic symptoms. This condition 

 terminated fatally if the diet was not changed. By substituting moist yeast 

 or autolyzed yeast for the dried preparation the rats could be maintained upon 

 the diet for a longer period. Similar results were obtained by adding to the 

 drinking water orange juice (which has neither growth-promoting nor main- 

 taining properties unless supplemented by yeast). 



The diets in which butter partially or wholly replaced lard had a slight 

 superiority over those containing lard alone. This superiority was more than 

 could be explained by the antiscorbutic properties of the butter. Even in this 

 case the existing deficiencies were not entirely corrected, since many rats de- 

 clined on the diet. Rats which failed on lard did not always recover on a 

 diet containing butter. 



It appeared possible also that yeast, on account of its high content in purins, 

 and perhaps other constituents, was not an ideal addition to the diet in 

 experiments of long duration, even in spite of its marked growth-promoting 

 power. " The impaired nutritive value of heated casein does not seem to be 

 due to destruction of amino acids but to destruction of vitamins." 



Studies on growth. — IV, The action of yeast fractions on the growth of 

 rats, C. Funk and A. B. Macallum {Jour. Biol. Chem., 27 {1916), No. 1, pp. 

 63-70, figs. 2). — Attempts were made to separate out a physiologically active 

 fraction from yeast, which would stimulate the growth of young laboratory 

 animals (rats). This was suggested by the close relationship existing between 

 the beri-beri and growth problems. The authors state that the same experi- 

 mental difficulties encountered in the investigation of the beri-beri vitamin were 

 encountered in this study, and that the problems of neither beri-beri nor 

 growth will be solved until more adequate methods for the isolation of the 

 vitamin are available. 



" The fractionation of j'east with phosphotungstic acid shows that the growth- 

 promoting substance is carried down with the precipitate, and a large part of 

 its activity is lost during the fractionation." 



The isolation of a growth-producing substance from sheep pancreas, W. H. 

 Eddy {Jour. Biol. Chem., 27 {1916), No. 1, pp. 113-126, figs. 9).— In attempting 

 to establish the presence of a vitamin in the water-soluble portion of the alco- 

 holic extract of sheep pancreas, feeding experiments were made with laboratory 

 animals (rats). The following solutions were used: A filtered water-soluble 

 portion of the alcoholic extract of pancreas ; Lloyd's reagent after shaking with 

 the water-soluble portion of the alcoholic extract; the filtrate from the 

 water-soluble portion after treatment with Lloyd's reagent ; and the phospho- 

 tungstic precipitate of the water-soluble portion after the removal of phospho- 

 tungstic acid with amyl alcohol. 



The results of these experiments seemed to prove that the water-soluble 

 poi'tion of the alcoholic extract of pancreas contains a substance capable of 

 inducing marked increase in growth. This substance, which is neither a pro- 

 tein nor a fatty substance, is removed from the extract without loss of power 

 by treatment with I>loyd's reagent, and is also precipitated by phosphotungstic 

 acid. Amino nitrogen determinations made on the different solutions used 



