SALTS OF AMMONIA, 453 



tained no uric acid ; if salts of ammonia were contained in the 

 urine, urate of ammonia would have been precipitated ; but there 

 was no deposit of this salt till after the addition of hydrochlorate of 

 ammonia. Scherer and Liebig* have also convinced themselves of 

 the absence of ammonia in normal urine. Heintz found that the 

 ordinary urinary sediments consist of urate of soda with a little 

 urate of lime, and only traces of urate of ammonia. 



Marchandf was the first who ascertained with certainty that 

 ammonia was present in the pulmonary exhalation ; by means of 

 the colourless heematoxylin discovered by ErdmannJ he could 

 detect it in the air of each individual respiration ; moreover, when 

 we employ sulphuric acid for the removal or determination of the 

 water in experiments on the respiration, it is always found to con- 

 tain ammonia. 



In certain diseased conditions of the system very considerable 

 quantities of ammonia are often found in the blood as well as in the 

 urine. Winter thought that the presence of ammonia in the blood 

 explained the phenomena of typhus, but ammonia may be detected 

 in the blood in all severe cases of acute disease, especially in variola 

 and scarlatina; there is no more constancy in the presence of ammonia 

 in the blood during typhus, than there is in the presence of the 

 crystals of the triple phosphate in the excrements. It is by no 

 means strange that in this state of the system the urine should 

 contain ammonia; the urine is, however, richest in ammonia when 

 it undergoes decomposition within the bladder, as in cases of 

 inveterate vesical catarrh or diseases of the spinal cord. 



HYDROCYANIC ACID. 



This acid never occurs preformed in the animal organism; even 

 in the most varied of the metamorphoses and decompositions which 

 occur during disease, we never meet with either the free acid or a 

 metallic cyanide. This is readily accounted for, when we recollect 

 that hydrocyanic acid, cyanogen, and the metallic cyanides, are only 

 produced from nitrogenous substances at a high degree of tempe- 

 rature. But in spite of this, certain physiological chemists have 

 shown no unwillingness either to assume that hydrocyanic acid, 

 either in conjugation or in combination, exists preformed in his- 



* Ann. d. Ch. u. Pharm. Bd. 50, S. 198. 



* Journ. f. pr. Ch. Bd. 33, S. 148, and Bd. 44, S. 35. 

 + Ibid. Bd. 27, S. 193-208. 



Ann. d. Ch. u. Pharm. Bd. 48, S. 329. 



