THE CHEMISTRY OF THE ANIMAL BODY. 507 



urine to dryness, fuse the residue with potassium nitrate (KN0 :t ), which oxidizes all the 

 sulphur to sulphate, take up with water and hydrochloric acid, add barium chloride, and 

 the precipitate (BaSOj represents the total sulphur present. Deduct the amount belong- 

 ing to sulphuric acid, previously determined, and the remainder represents the neutral 

 sulphur. 



Metabolism of Sulphur. — The total amount of sulphur in the urine 

 runs proportionally parallel with the amount of nitrogen ; that is to say, the 

 amount is proportional to the amount of proteid destroyed. The amount of 

 ethereal sulphate is dependent upon the putrefactive production of indol, 

 skatol, phenol, and cresol in the intestinal canal, which on absorption form a 

 synthetical combination with the traces of sulphate in the blood. Concerning 

 neutral sulphur it is known that taurin is one source of it. If taurin be fed 

 directly, the amount of neutral sulphur in the urine increases (Salkowski), and 

 in a dog with a biliary fistula the neutral sulphur decreases but does not en- 

 tirely disappear. 1 In a well-fed dog with a biliary fistula Yoit 2 found the 

 quantity of sulphur in the bile to be about 10 to 13 per cent, of that in the 

 urine. This biliary sulphur (taurin) is normally reabsorbed, as the quantity 

 of sulphur in the feces (FeS, Na 2 S) is small and derived principally from pro- 

 teid putrefaction. The amount of neutral sulphur in the urine is greatest 

 under a meat diet, least when fat or gelatin is fed; the sulphur of gelatin 

 is very small in quantity. In dyspncea the amount of neutral sulphur in- 

 creases in the urine, on account of insufficient oxidation. 3 The neutral sul- 

 phur of the urine includes potassium sulphocyanide (originally derived from 

 the saliva), likewise a substance which on treatment with calcium hydrate 

 yields ethyl sulphide, (C 2 H 5 ) 2 S, 4 and there are present other unknown com- 

 pounds (see p. 547). When an animal eats proteid and neither gains nor 

 loses the same in his body, the amount of sulphur ingested is equal to the 

 sum of that found in the urine and feces. If sulphur be eaten, it partially 

 appears as sulphate in the urine. Sulphates eaten pass out through the urine. 

 They play no part in the life of the cell. 



Chlorine, CI = 35.5. 



Free chlorine is not found in the organism, and when 1 neat lied it vigor- 

 ously attacks the respiratory mucous membranes. Chlorine is found combined 

 in the body as sodium, potassium, and calcium chlorides, as hydrochloric acid, 

 and it is said to belong to the constitution of pepsin. 8 



Hydrochloric Acid, HC1, is found to a small extent in the gastric juice. 



Preparation. — (1) If sunlight acts on a mixture of equal volumes of chlorine and 

 hydrogen, they unite with a loud explosion. 



1 Kunkel : Archivfur </i>< gesammte Physiologic, 1877, Bd. 14, S. 353. 



2 Zeitsekrifi fur Biologie, 1894, Bd. 30, S. 554. 



3 Harnack and Kleine: Zeitachrift fur Biologie, 1899, Bd. 37, S. 417. 



4 J. J. Abel : Kitsch rift fur physiologisehe ('hemic, 1894, 1!<1. 'Jo, S. 253. 



5 E. O. Schoumow -Simanowski : Archiv fiir exper. Pathologie und Pharmakologie, 1894, Bd. 

 33, S. 336. 



