166 EXPERIMENT STATION RECORD. 



Water wag also used as a beverage. The chlorin, sulphur, phosphoric acid, and 

 nitrogen in the diet was determined, the amount of nitrogen furnished per day 

 ranging from 18.80 to 19.05 gm. 



Laws governing the chemical composition of urine, 0. Folin (Amer. Jour. 

 Physiol, 13 (1905), No. /, pp. 66-115).— A study of the urine of a subject who was 

 accustomed to live on a diet containing small amounts of protein showed that the 

 constituents were not present in the same proportions as in so-called normal urine, 

 the urea nitrogen constituting a much smaller percentage of the total than is gener- 

 ally the case. Differences in the proportions of other constituents were also found. 



A number of studies were, therefore, undertaken with healthy subjects in which 

 a period of 3 or 4 days on a diet furnishing about 19 gm. of nitrogen was followed by 

 a period of 7 or 10 days' duration with a diet made up of 300 cc. of cream and 400 gm. 

 of pure arrowroot starch, the total nitrogen supplied being only about 1 gm. per day. 

 The experiments closed with a period of 1 or 2 days' duration on a diet like that in 

 the first period. 



The results obtained with the different subjects were uniform, quantitative changes 

 in the daily proteid metabolism on the different diets being accompanied, according 

 to the author, by pronounced changes in the distribution of the urinary nitrogen and 

 sulphur, and the author believes that "the distribution of the nitrogen in urine 

 among urea and the other nitrogenous constituents depends on the absolute amount 

 of total nitrogen present. . . . The distribution of the sulphur in urine among the 

 3 chief normal representatives — inorganic sulphates, ethereal sulphates, and 'neutral 

 sulphur' — depends on the absolute amount of total sulphur present." 



As regards the different urine constituents "the absolute quantity of creatinin 

 eliminated in the urine on a meat-free diet is a constant quantity, different for differ- 

 ent individuals, but wholly independent of quantitative changes in the total amount 

 of nitrogen eliminated. . . . When the total amount of protein-metabolism is greatly 

 reduced, the absolute quantity of uric acid is diminished, but not nearly in propor- 

 tion to the diminution in the total nitrogen, and the per cent of the uric acid nitrogen 

 in terms of the total nitrogen is therefore much increased. . . . With pronounced 

 diminution in the protein metabolism (as shown by the total nitrogen in the urine), 

 there is usually, but not always, and therefore not necessarily, a decrease in the 

 absolute quantity of ammonia eliminated. A pronounced reduction of the total 

 nitrogen is, however, always accompanied by a relative increase in the ammonia 

 nitrogen, provided that the food is not such as to yield an alkaline ash." 



As regards the urea, this suffers a relative as well as an absolute diminution with 

 a diminution in the total proteid metabolism, 60 per cent being recovered in the 

 urine, when the total nitrogen elimination is reduced to 3 or 4 gm. as "compared with 

 about 90 per cent of the total nitrogen in normal urine. 



Decided diminutions in the daily elimination of total sulphur were accompanied 

 by reductions in the percentage of sulphur present as inorganic sulphates, the reduc- 

 tion being as great as in the case of nrea. The neutral sulphur elimination was anal- 

 ogous to that of creatinin and, according to the author, it represents products which 

 in the main are independent of the total amount of sulphur eliminated by protein 

 catabolism. The percentage of total sulphur excreted as ethereal sulphates increased 

 and, according to the author, these ethereal sulphates represent a form of sulphur 

 metabolism which becomes more prominent when the food contains little or no 

 protein. 



The volume of urine it was found depended entirely upon the amount of water 

 consumed. The chlorin elimination, as is generally conceded, was found to vary 

 chiefly with the volume of urine provided the amount consumed was constant. 



Studies of the acidity of urine and methods of estimating acid led to the conclu- 

 sion that "the phosphates in clear acid urine are all of the monobasic kind, and the 

 acidity of such urines is ordinarily greater than the acidity of all the phosphates. 



