542 APPENDIX. 



of sulphuric acid, and then distilled. The distillate which was 

 obtained after the application of phosphoric acid, does not exhibit 

 this supposed nitric-acid reaction even when the urine has been 

 previously treated with some drops of nitric acid. Jaffe modified 

 this experiment in various ways, but the methods we have already 

 given are sufficient to show that the presence of nitric acid in the 

 urine cannot be proved by Jones's method, even when it occurs in 

 moderate quantities, and that Price's method for detecting nitric 

 acid is altogether inapplicable when sulphurous acid is present. 

 We must therefore, for the present, leave the somewhat improbable 

 view of the conversion within the organism, of ammoniacal salts 

 into nitric acid, as a subject requiring further investigation before 

 it can be regarded as settled. 



[Dr. Bence Jones* has defended his former views in a memoir 

 recently read (June 15, 1854) before the Royal Society, "On the 

 oxidation of ammonia in the human body." In this paper he 

 describes a series of experiments, from which it results : 



1st. That in Price's test sulphurous acid produces exactly the 

 opposite effect to nitrous acid, and even hinders nitrous acid from 

 liberating iodine from hydriodic acid. 



2nd. That phosphoric acid, when mixed with urine containing 

 nitre, and distilled very low, does liberate nitrous acid ; though 

 when used instead of sulphuric acid, it does not enable the nitrous 

 acid to be detected so readily as when the latter acid is employed. 

 " Hence (he observes) the experiments performed in 'Professor 

 Lehmann's laboratory by Herr Jaffef, do not invalidate Price's 

 test for nitrous acid in the way Professor Lehmann supposes ; 

 and by again repeating some of my former experiments, I still 

 arrive at the conclusion that when ammonia is taken into the 

 body, nitric acid may be detected in the urine, but that the 

 quantity which can be made to appear is so small that the most 

 delicate method is required for its detection. This, however, is no 

 proof that a much larger quantity may not be lost in the process 

 for obtaining it from the urine." G. E. D.] 



(50) Addition to p. 420, line 21. RankeJ found that after 

 the use of amygdalin considerable quantities of formic acid passed 

 into the urine, an observation which I thoroughly confirmed in 

 my experiments on the injection of amygdalin into the veins. 



* Proceedings of the Royal Society. Vol. 7> p. 94. 

 t Jotirn. f. pr. Chem. Bd. 59, S. 238. 

 Ibid. Bd. 56, S. 17. 



