3C ORGANIC CONSTITUENTS. 



Wlien tlie extract lias been reduced to the consistence of a 

 syrnp, it is treated with alcohol of 83^, which throA\ s down a 

 copious brown precipitate. The clear alcoholic fluid is removed 

 and evaporated. It forms a brown extract^ which is devoid of 

 the aromatic odour tliat is perceptible in the spirit-, and alcohol- 

 extract of flesh. The residue is evaporated to the consistence 

 of a thin extract, and then treated with absolute alcohol, which, 

 when evaporated, leaves a very small amount of alcohol-extract. 



Wate7'-extract of blood. It is of a dark brown colour, and 

 possesses a strong taste of salt. Its reaction is slightly alkaline, 

 and there is nothing remarkable about its odour. On incine- 

 ration it leaves an alkaline ash, which effervesces on the addi- 

 tion of an acid. 



The following are its most important chemical relations. 



Acetic acid produces a turbidity which only disappears in a 

 great excess of the test : ferrocyanide of potassium throws down 

 a slight precipitate from the clear acid fluid, consisting of 

 albumen. 



Neutral and basic acetate of lead produce a copious brown 

 precipitate ; bichloride of mercury, e^en in excess, produces no 

 apparent change. Infusion of galls induces merely a slight 

 turbidity. 



Spirit-extract of blood is of a dark brown colour, and a 

 strongly salt taste. During evaporation it becomes covered with 

 a coating of salts ; and, after a certain degree of concentration, it 

 solidifies, in consequence of the amount of the salts. It leaves 

 a porous coal, which does not very easily burn to a white ash. 

 This ash is strongly alkaline, and effervesces briskly on the 

 addition of an acid. 



The aqueous solution of the spirit-extract has a yery feeble 

 alkaline reaction. 



Acetic acid produces a slight turbidity, which disappears on 

 the addition of a considerable excess of the test. 



Neutral and basic acetates of lead and infusion of galls j)ro- 

 duce copious precipitates ; bichloride of mercury effects no 

 apparent change. 



Alcohol-extract of blood. When the alcohol in which this 

 substance is contained is evaporated to the consistence of an 

 cxtrfict, and then warmed with ether, w^e obtain a greenish 

 brown matter, which, after the evaporation of the ether, is 



