122 COMPOSITION OF FIBRINE, 



oxidised state. All these substances, when heated 

 with a moderately strong solution of potash, yield 

 the sulphur which we find in the solution as sul- 

 phuret of potassium ; and on the addition of an 

 acid it is given off as sulphuretted hydrogen. When 

 pure fibrine or ordinary albumen is dissolved in a 

 weak solution of potash, and acetate of lead is added 

 to the solution, in such proportion that the whole of 

 the oxide of lead remains dissolved in the potash, 

 the mixture, if heated to the boiling point, becomes 

 black like ink, and sulphuret of lead is deposited 

 as a fine black powder. 



It is extremely probable, that by the action of 

 the alkali the sulphur is removed as sulphuretted 

 hydrogen, the phosphorus as phosphoric or phos- 

 phorous acid. Since, in this case, sulphur and phos- 

 phorus are eliminated on the one hand, and oxygen 

 and hydrogen on the other, it might be concluded 

 that fibrine and albumen, when analysed with their 

 sulphur and phosphorus, would yield a larger pro- 

 portion of oxygen and hydrogen than is found in 

 proteine. But this cannot be shewn in the analysis ; 

 for fibrine, for example, has been found to contain 

 0*36 per cent, of sulphur. Assuming, then, that: 

 this sulphur is eliminated by the alkali in combina- 

 tion with hydrogen, proteine would yield 0-0225 

 per cent, less hydrogen than fibrine ; instead of the 

 mean amount of 7'062 per cent, of hydrogen, the 

 proteine should yield 7'04 per cent. In like man- 

 ner, by the elimination of the phosphorus in combi- 



