22 



January 30, 1851. 

 SIR RODERICK IMPEY MURCHISON, V.P., in the Chair. 



The following papers were read : — 



1. "On the Oxidation of Ammonia in the Human Body, with 

 some remarks on Nitrification." By Henry Benee Jones, M.D., 

 F.R.S. &c. Received December 18^ 1850. 



The author having shown, in a paper lately communicated to the 

 Royal Society, that the effect of tartrate of ammonia on the acidity 

 of the urine was totally different from that of tartrate of potash, and 

 that carbonate of ammonia, taken in very large quantities, did not 

 produce any alkaline reaction of the urine, but that, on the con- 

 trary, the acidity was rather increased than diminished by such 

 doses, repeated the experiments with carbonate of ammonia, hoping 

 to obtain more decided results. Although, from these experiments, 

 it was again apparent that no diminution of the acid reaction re- 

 sulted from taking carbonate of ammonia, yet the fact of any great 

 increase in the acidity of the urine could not be determined. In his 

 former paper, the author suggested that an inquiry into the occur- 

 rence of nitric acid in the urine would probably give the solution of 

 this unexpected effect of carbonate of ammonia: and he was led to 

 undertake the experiments described in the present paper with the 

 view of detecting the presence of that acid under particular circum- 

 stances. 



The indigo test for nitric acid being more delicate than the pro- 

 tosulphate of iron test, it was chiefly employed ; but a mixture of 

 starch with a drop or two of hydriodate of potash and hydrochloric 

 acid was found to be a far more delicate test than either. Begin- 

 ning with 10 grs, of nitrate of potash added to 10 oz. of urine, it 

 was found at last that as little as 1 gr. of nitre to 10 oz. of urine 

 could be detected with the greatest certainty and clearness when the 

 starch test was used; but this quantity could not be detected as 

 surely by the indigo test. 



Experiments are described in which carbonate of ammonia was 

 given, in doses varying from 40 grs. to 7 grs., to a healthy man in 

 whose urine no nitric acid could previously be detected ; and the 

 urine was tested at intervals of several hours after each dose. From 

 these it appears that 10 grs. was the smallest quantity that gave de- 

 cided evidence of nitric acid by both tests. 



Having satisfied himself that when carbonate of ammonia was 

 taken small quantities of nitric acid passed off in the urine, the 

 author made similar experiments with tartrate of ammonia, admi- 

 nistered in doses of 60 and 40 grs.; and in each case the starch test 

 gave evidence of the presence of nitric acid in the urine some hours 

 after. Similar experiments with the muriate of ammonia are next 

 described ; and in these the presence of nitric acid in the urine was 

 readily detected three hours after the administration of the dose, 

 even when it was so small as 10 grs. 



From an experiment described in the paper, it was shown, that by 



