150 ESSAY IX. 



urine ; but as such urine likewise grows turbid, and 

 deposits the same sediment when kept in close vessels, 

 and redissolves it again on being exposed to a sufficient 

 degree of heat, it appears evident that such a menstruum 

 is neither present nor requisite. 



SECTION IX. 



All urine contains some animal earth or lime combined 

 with phosphoric acid, and by the superabundance of acid 

 this earth is kept dissolved. It is owing to this super- 

 abundance that urine imparts a red colour to paper coloured 

 with lacmus. If this superabundant acid be saturated 

 with volatile caustic alkali, a white powder is precipitated. 

 3J drms. of this powder, when dried, are obtained from 

 four cans of urine. I dissolved it in nitrous acid ; on 

 adding vitriolic acid some gypsum was precipitated. After 

 all the nitrous acid was evaporated, an acid remained, 

 which precipitated lime-water, and, when mixed with lamp- 

 black, yielded phosphorus on distillation ; consequently 

 this powder really contains lime and phosphoric acid. 



SECTION X. 



According to these experiments, all urine contains, 

 besides the substances already known (viz. sal ammoniac, 

 common salt, digestive salt, Glauber's salt, microcosmic salt, 

 sal perlatum, and an oily extractive matter), a concrete acid, 

 hitherto unknown, or the calculus, and animal earth. It 

 is remarkable that the urine of the sick is more acid, 

 and contains more animal earth than that of healthy 

 persons. 



