468 EXPERIMENT STATIOjST RECORD. [Vol.41 



tents were regurgitated at intervals tliroughout tlie curding period of the uiillv, 

 tlie otiier in wliicli tlie stomaoli was completely emptied a half hour after a pint 

 of milk hud been ingested. The results obtained, which are described and illus- 

 trated by photographs, may be summarized as follows : 



Milk drunk rapidly left the stomach sooner and produced a smaller curd mass 

 than milk drunk slowly or sipped. Raw Avhole milk formed firm, white, rubber- 

 like curds, the maximum curd formation taking place about one hour after the 

 milk had entered the stomach. Milk which had been boiled five minutes formed 

 small, soft, flaky, yellow curds which left the stomach sooner and were much 

 more easily digested than the tough curds from the raw milk. A mixture of 80 

 per cent boiled whole milk and 20 per cent raw whole milk gave curds similar in 

 character to those obtained from the ingestion of raw whole milk. These re- 

 sults would indicate that, dietetically, boiled milk is to be preferred to the raw 

 product except for the fact that its antiscorbutic value may have been -lowered. 



Skim milk formed large, harder curds than whole milk. The curds of 

 raw milk were larger and harder than those of the boiled milk. The fat con- 

 tent is considered to be an important factor in determining the character of the 

 curd in milk. In general the more fat the less curd, and the smaller and softer 

 the curd. When 40 per cent cream was drunk, no curds were formed during 

 the first half hour. Milk of high fat concentration was also very slow to leave 

 the stomach. 



The curds of pasteurized milk were intermediate in character between the 

 curds of raw and boiled milk. The drinking of water before the milk was in- 

 gested tended to make the curds somewhat smaller and softer. The tempera- 

 ture of the milk was found to have but little effect on time of curd formation, 

 although lowering the temperature had a slight tendency to delay the formation 

 of curds. 



The minimum of sugar and fat, H. Biekry (Compt. Rend. Soc. Biol. [Paris}, 

 82 {1919), No. 3, pp. 124-127). — Arguments are given to prove the necessity of 

 a minimum of fat as well as a minimum of carbohydrate (E. S. R., 40, p. 563) 

 in the diet. The importance of certain fats in furnishing vitamins is pointed 

 out. 



Nutritional studies on the growth of frog larvae (Rana pipiens), A. D. Eii- 

 METT and F. P. Allen {Jour. Biol. Chem., 38 {1919), No. 2, pp. 325-3U, Pls. 4, 

 fig. 1). — This is a preliminary report of a series of nutritional studies in which 

 tadpoles were used in place of larger animals for the purpose of determining 

 facts regarding their nutrition with respect to size and degree of metamor- 

 phosis. Immediately after hatching, the tadpoles were placed in enameled trays 

 in groups of 500 each and fed at specified times on synthetic diets so arranged 

 as to show the effect of various modifications. The record of progress of 

 growth was obtained by means of photographs taken each week of a selected 

 group from each colony. Histological studies were also made of representative 

 specimens. The results are summarized of the effect of diet upon the size and 

 upon the development of hind legs of the tadpole, and the following tentative 

 conclusions drawn : 



A large aniount of fat in the diet was very in.1urious to both growth (body 

 size) and development of hind legs. Vitamins of both the water-soluble and fat- 

 soluble type appeared to be necessary for normal growth and development. The 

 lack of water-soluble B was slightly more apparent than that of fat-soluble A. 

 The amount of protein, from 10 to 20 per cent of lactalbumin, seemed to have 

 little effect on the development of hind legs whether both vitamins, one, or 

 neither were present, but the high protein-fed tadpoles were largest when both 

 A-itamins were present. The quality of the protein was an important factor in 



