THE CHEMISTRY OF THE ANIMAL BODY. 951 



hydrochloric acid and barium chloride be added, the preformed sulphuric acid & precip- 

 itated as barium sulphate (BaSOJ, which may be washed, dried, and weighed. If 100 

 cubic centimeters of urine be mixed with an equal volume of a solution containing barium 

 chloride and hydrate, filtered, and one-half the filtrate ( = 50 cubic centimeters of urine, 

 now free of preformed sulphate) be strongly acidified with hydrochloric acid and boiled, the 

 ethereal sulphates will be broken up, and the resulting precipitate of barium sulphate will 

 correspond to the ethereal sulphuric acid. To determine the neutral sulphur, evaporate 

 the urine to dryness, fuse the residue with potassium nitrate (KNO 3 ), which oxidizes all 

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

 and the precipitate (BaS0 4 ) represents the total sulphur present. Deduct the amount 

 belonging 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 Voit 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 

 burns apparently to sulphuric acid. 3 The neutral sulphur of the urine includes 

 potassium sulphocyanide (originally derived from the saliva), likewise a sub- 

 stance which on treatment with calcium hydrate yields ethyl sulphide, 

 (C 2 H 5 ) 2 S, 4 and there are present other unknown compounds. 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, Cl = 35.5. 



Free chlorine is not found in the organization, and when breathed it vigor- 

 ously attacks the respiratory mucous membranes. Chlorine is found combined 

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

 and it is said to belbng to the constitution of pepsin. 5 



1 Kunkel : Arehiv fiir die gesammte Physiologic, 1877, Bd. 14, p. 353. 



2 Zeitschrift fur Biologie, 1894, Bd. 30, p. 554. 3 Voit, Op. til, p. 537. 



4 J. J. Abel : Zeitschrift fiir physiologische Chemie, 1894, Bd. 20, p. 253. 



5 E. O. Schoumow-Simanowski : Arehiv fiir exper. Pathologic und Pharmakologie, 1894, Bd. 

 33, p. 336. 



