128 



Scientific Proceedings (34). 



even in large amounts, was capable of liberating all the ammonia 

 from triple phosphate, whereas sodium hydroxide, in comparatively 

 small amounts, discharged the ammonia completely. The first 

 condition was, therefore, solved. It now remained for us to ascer- 

 tain whether sodium hydroxide would produce ammonia from such 

 amino compounds as urea. 



After many preliminary trials, in some strictly comparative tests 

 on normal urines, I found that from 0.5 gram to i gram of sodium 

 hydroxide, plus about 16 grams of sodium chloride, gave results 

 that were in perfect accord with those of the Folin method. Over 

 fifty comparisons were made. 



In Oder to ascertain positively whether the modified method 

 would produce ammonia from non-ammoniacal radicals, weighed 

 samples of urea, uric acid, glycocoU, taurin, leucin, tyrosin and 

 hippuric acid were added separately and also collectively to 25 c.c. 

 portions of urine and the results compared with the figures for the 

 ammonia obtained from equal volumes of the original urine. In 

 no case was any increase obtained. The tests were repeated, but 

 20 c.c. of a standard solution of ammonium chloride were substi- 

 tuted for the 25 c.c. of the urine. In these cases, also, no increase 

 of ammonia output was obtained. 



As a final test of the efficiency of the modified method the 

 ammonia content was determined in a normal urine by both the 

 Folin method and the modified method. Then to equal volumes 

 of the original urine 0.5 gram samples of triple phosphate were 

 added, and the ammonia contents again determined by both 

 methods. The ammonia was also determined in separate portions 

 of the triple phosphate. 



The results of these directly comparative tests showed that, 

 witli the modified method, the ammonia obtained from the urines to 

 which the triple phosphate had been added exactly equaled the total 

 amount of ammonia obtained from the corresponding urine and 

 the triple phosphate separately whereas, ivith the Folin method, only 

 from 70 to 80 per cent, of the total amount of this ammonia was 

 recovered. 



