766 • EXPERIMENT STATION RECORD. [Vol.85 



Carbohydrate-rich, fat-poor diet ; intermediate diet ; and fat-rich, carbohydrate- 

 poor diet. Each diet was preceded and followed by a period of several days, 

 during which time a standard diet was given. The following conclusions are 

 drawn : 



" Nitrogen in the form of protein added to a carbohydrate diet is retained 

 in greater amount than when added to a fat diet of equal caloric value. Nitro- 

 gen given in the form of caseinogen is more completely retained than when 

 given in the form of gelatin. The addition of meat extract to gelatin does not 

 increase the amount of nitrogen retained." 



The protein metabolism of an infant, F. B. Tai.bot and J. L. Gamble {Amer. 

 Jour. Diseases Children, 12 (1916), No. 4, pp. S33-3U, figs, i).— This paper 

 reports observations upon an infant receiving a diet in which the protein was 

 increased in each successive period. It was found that the metabolism went 

 on in a normal manner in spite of the increase of protein. 



" The endogenous metabolism of uric acid, creatiuin, and ethereal sulphates 

 was maintained on a very constant level, while the exogenous metabolism, 

 namely, urea, creatin, inorganic sulphates, and the metabolism of phosphates, 

 chlorids, and undetermined nitrogen increased with the protein in the food. 

 The fat and carbohydrate absorption was within normal limits, although the 

 fat utilization . . . [in two periods] was almost outside normal limits. The 

 retention of nitrogen suddenly dropped in the last period, even though there 

 was a greater intake and absorption of nitrogen. This loss was found in the 

 stools, in which casein curds were found in large numbers. The ammonia in 

 the stools increased with the increasing protein intake, and may be considered 

 an index of intestinal putrefaction." 



Effect of autolysis upon muscle creatin, R. Hoagland and C. N. McBryde 

 (V. S. Dept. Agr., Jour. Agr. Research, 6 (1916), No. U, pp. 535-547).— The 

 data obtained in these experiments are reported as a contribution to the 

 knowledge of the source and method of production of creatinin in the animal 

 body. 



In one series of experiments, under aseptic conditions, pieces of muscular 

 tissue were cut from the hind quarter of a steer, sealed in sterile dishes, and 

 allowed to undergo aseptic autolysis at 37° C. for periods ranging from 7 to 100 

 days, at the end of which the percentages of free and total creatinin were 

 determined. Only such samples as were found on bacteriological examination 

 to be sterile were used. In another series antiseptic methods were employed, 

 chiefly as a check and for comparison with the aseptic method. Pieces of mus- 

 cular tissue were finely ground with sand and placed in flasks with salt solu- 

 tion, chloroform and toluol being added to prevent bacterial growth. These were 

 kept at 37° for periods ranging from 2 to 84 days and the percentages of total 

 and free creatinin determined. In both series of experiments analyses were 

 made of samples of the fresh muscular tissue for comparison. 



The resiilts of these experiments show that muscular tissue has the power, 

 in a marked degree, to convert creatin into creatinin and has the ability, in an 

 appreciable degree, both to produce and destroy creatinin. It was also found 

 that during the course of autolysis an equilibrium is finally established between 

 creatin and creatinin. This, in the opinion of the authors, denotes that " in auto- 

 lyzlng muscular tissue the rate of reaction Is very greatly accelerated, but that the 

 total extent of the change is the same in either case. The more rapid change 

 of creatin into creatinin in the autolyzing tissue may safely be assiuned to be 

 due, in large part, at least, to enzym action. This conforms to our idea as to 

 the catalytic nature of enzyms. The gradually reduced rate of change of 

 creatin to creatinin during autolysis is in conformity with the law of mass 

 action." 



