Q8 VEGETABLE SUBSTANCES. 



chloric or nitric acid, together with the sulpho- 

 cyanate (p.4o), by which ferrous compounds which 

 may be present are oxydized, when their presence 

 is indicated by the above red color. 



SULPHUR 



Has been found in the pure crystalline state only 

 in those bacteria which live in thermal springs or 

 on rotting algae, and which liberate sulphuretted 

 hydrogen. 



Sulphur is soluble in carbon-bisulphide. For 

 the violet reaction with the nitro-prussiate of so- 

 dium in alkaline fluids see page 39. It gives no 

 reaction in an aqueous solution of perosmic acid, 

 and thus may be easily distinguished micro-chemi- 

 cally from the fatty oils, to which it frequently 

 bears no small resemblance. 



