250 LECTURE XI. 



gration of the albumins, and that this is decomposed in the same manner 

 as the cystine which is artificially introduced. 



The sulphuric acid of the urine has been subjected to thorough study. 

 It was found that it occurred in various combinations. If we add barium 

 chloride to urine which has been previously acidified, barium sulphate will 

 precipitate at once. A further turbidity will appear after filtering this 

 off and boiling with hydrochloric acid. E. Baumann 1 satisfactorily 

 explained this behavior of sulphuric acid in urine. The sulphuric acid 

 at first precipitated is derived from sulphates salts of sulphuric acid. 

 That which is obtained after boiling with hydrochloric acid is due to 

 sulphuric acid which has been in combination with different aromatic 

 substances in the urine. The hydrochloric acid decomposes these aromatic 

 compounds also called sulphuric acid esters into the aromatic com- 

 ponent and sulphuric acid, the latter being then precipitated by barium 

 chloride. The sulphuric acid esters themselves form soluble barium salts. 

 We shall see that sulphuric acid forms the same kinds of compounds with 

 these that we found it does with glycocoll and glucuronic acid. We wish 

 to add at this point that some sulphur compounds still remain in solution 

 even after the sulphur in the sulphuric acid esters have been precipitated. 

 This is the " neutral sulphur " mentioned above. In order to detect this 

 sulphur it is necessary to oxidize it, thus converting it into sulphuric acid, 

 when it will be precipitated by barium chloride. By these methods we 

 are able to isolate all three varieties of combined sulphur in the presence 

 of one another. The determination of the total sulphur together with 

 that of the total nitrogen in the urine gives us a very good conception of 

 the course of the disintegration of albumin. 



We must not forget to mention that sulphocyanic acid, or thiocyanic 

 acid, HCNS, also occurs in urine. Gscheidlen 2 found it invariably present 

 in the urine of human beings, horses, calves, dogs, cats, and rabbits. In 

 human urine 0.2 to 0.8 gram is eliminated daily. The sulphocyanic acid 

 comes from the saliva, being formed in the salivary glands. This acid 

 reaches the blood-stream by absorption. If all the ducts of the salivary 

 glands are cut and the saliva discharged externally, sulphocyanic acid no 

 longer appears in the urine. Its origin and significance have never been 

 explained. 



1 Ber. 9, 54 (1876). 



3 Tageblatt 47, Versammlung deutscher Naturf, u. Aerzte in Breslau, 1874. 



