96 LABORATORY WORK IN PHYSIOLOGICAL CHEMISTRY. 



as the ethereal or conjugated sulphates. The strength of 

 combination and manner of detection of the sulphate radical 

 has been studied under the inorganic salts. The amount 

 of the conjugate sulphates varies from 0.09 to 0.6 grm., 

 being dependent, as it would be expected from their origin, 

 upon the extent of putrefaction in the intestine. 



The Phenol and p-Cresol sulphates exist in normal 

 urine in relatively small amounts, about 30 mg. for twenty- 

 four hours. They may be isolated and detected as follows: 



Treat the urine with | its volume of 25 per cent H 2 S0 4 

 and distil off T V of the volume of the solution. Use this 

 distillate for the succeeding reactions: 



(a) Add some Millon's reagent to a little of the solution. 

 Warm. Compare this with the test under protein and 

 tyrosine. 



(6) To a few c.c. of the solution add a trace of neutral 

 ferric chloride solution. When did you use this reaction 

 before? Add a drop of HC1. 



(c) To 10 c.c. of the distillate add some bromine-water. 

 Note the whitish crystalline precipitate of tribromphenol. 



The combinations with Pyrocatechinol and hyurochinol 

 originate after the ingestion of these bodies or of phenol. 

 The urine containing them becomes brown on standing ("car- 

 bolic urines "). 



Indole and Skatole (/3-methyl indole) do not unite with 

 the sulphuric acid directly as such, but first suffer an oxida- 

 tion by which indoxyl and skatoxyl are formed; they then 

 combine and appear in the urine as potassium indoxyl or 

 skatoxyl sulphate. The former is called animal indican 

 and is not to be confounded with the indican of plants. The 

 skatoxyl compound is only present in minimal quantities 

 and not infrequently is absent entirely. 



