1917] FOODS — HITMAK NUTRITION. 163 



times further experiments are necessary before tlie laws of ammonia excretion 

 in tlie rabbit can be formulated. Calcium elimination is too variable to justify 

 inferences being drawn under the experimental conditions. 



" The results obtained indicate that the creatinuria observed upon a grain 

 diet can not be explained upon the hypothesis of food insufficiency." 



The volume of urine in young healthy adults on a constant diet, T. Addis 

 and C. K. Watanabe {Jour. Biol. Chem., 27 (1916), No. 1, pp. 267-272) .—In 

 connection with the above investigation a large amount of data was obtained 

 regarding the volume of urine of subjects on a constant water intake, which 

 are summarized as follows : 



"The volume of urine in normal individuals on a constant diet with the 

 same water intake is extremely variable for any single day or part of a day. 

 The average volume of the last three days of the diet, when the water intake 

 was 2,070 cc. varied in 20 individuals from 1,013 to 1,712 cc. for a 24-hour 

 period, from 684 to 1,195 cc. for the first 12 hours of the day, and from 501 

 to 7S8 cc. for the first 8 hours of the day. The percentage of the 24-hour 

 volume excreted during the 12 hours of the night did not exceed 47 per cent 

 in any subject. . . . 



"An increase of 1,000 cc. a day in the water intake more than doubled the 

 volume of urine but did not appreciably increase the rate of urea excretion. 



"An increase in the rate of urea excretion induced by the ingestion of urea, 

 the water intake remaining constant, was accompanied by a considerable in- 

 crease in the volume of urine." 



The rate of urea excretion. — I, A criticism of Ambard and Weill's laws of 

 urea excretion, T. Addis and C. K. Watanabe {Jour. Biol. Chem., 24 {1916), No. 

 3, pp. 203-220). — From a study of the relationship between the concentration 

 of urea in the blood and the rate of urea excretion, when the concentration 

 of urea in the urine is the same, and the relationship between the concentra- 

 tion of urea in the urine and the rate of urea excretion, when the concentra- 

 tion of urea in the blood is the same, the authors concluded as follows : 



" The rate of urea excretion in man varies under physiological conditions in 

 a manner which can not be explained by the concentrations of urea in the 

 blood and urine. There is a tendency for an increased rate of urea excretion 

 to exist with higher blood urea concentration in cases in which the urine 

 concentration is the same, and for an increased rate of urea excretion to be 

 accompanied by a lowering of the urea concentration in the urine in cases 

 in which the blood concentration is the same. This relationship, however, is 

 one which is frequently obscured, even in individuals under the same con- 

 ditions as regards nitrogen and water intake. Other factors than urea con- 

 centration are important in determining the rate of urea excretion by the 

 normal kidney." 



The rate of urea excretion. — II, The rate of excretion of administered urea 

 in young healthy adults on a constant diet, T. Addis and C. K. Watanabe 

 {Jour. Biol. Chem., 27 {1916), No. 1, pp. 249-266).— A study was made of the 

 rate of excretion of urea administered to young, healthy adults who were on 

 a constant diet, the aim being to obtain detailed information regarding the 

 range of variation in the function of a normal kidney under normal conditions. 



In 39 experiments no evidence of variability in kidney action was obtained 

 in the work of excreting performed urea added to a constant diet. From this 

 it is concluded that a normal kidney under constant conditions possesses a 

 high degree of constancy of function. 



" The rate of excretion of the administered urea during successive periods ot 

 the 24 hours showed that the repetition of large doses of urea did not elicit the 

 condition which has been described as * kidney fatigue.' 



