1024 FIBRIN. 



lead, and many other metallic solutions. Insoluble compounds 

 are formed, one of which is of considerable interest, that of 

 chloride of mercury ; as albumen is had recourse to as an anti- 

 dote to corrosive sublimate, the white of one egg precipitating 

 about four grains of that salt. To form the albuminate of chlo- 

 ride of mercury, a solution of corrosive sublimate is added in 

 excess to a solution of albumen, and the white flaky precipitate 

 is collected on a filter and washed. It is slightly soluble in 

 water, resembles the curd of milk and is insipid ; it dissolves 

 in a solution of common salt. Lassaigne finds that when 

 heated it coagulates ; the albumen appearing to abandon 

 chloride of mercury, at the same time, which may afterwards 

 be dissolved out by ether. It consists, when dried, according 

 to the same chemist, of 98.4 parts of albumen and 6.6 parts 

 of chloride of mercury, in 100 parts. Chloride of mercury 

 forms a similar compound with fresh fibrin. The solution of 

 albumen is also precipitated by an infusion of nutgalls. 



Soluble albumen dissolves phosphate of lime, a salt, of which 

 about 2 per cent may be separated from coagulated albumen 

 by dilute hydrochloric acid. Metallic silver is blackened by 

 albumen, which always contains sulphur, whether the albumen 

 is soluble as in the egg and blood, or insoluble as in the 

 hair. 



FIBRIN. 



This principle is contained by the living blood in a soluble 

 state, but soon coagulates when withdrawn from the blood 

 vessels. It forms the clot of coagulated blood, and constitutes 

 muscular fibre. It is obtained in threads on stirring newly 

 drawn blood with a stick ; or by pressing the coagulum in a 

 small stream of water, till it becomes colourless and consists of 

 soft fibres. It is purified by washing it with ether, or warm 

 anhydrous alcohol which dissolves out fat. 



Fibrin affects a remarkable kind of aggregation, the globules 

 of which it is composed, attaching themselves to each other by 

 their ends, so as to form threads or fibres. In the humid state 

 it possesses the characteristic softness and elasticity of the 

 flesh of animals, and contains about three-fourths of its weight 

 of water. It may be deprived of this water in dry air, and 



