COMPOUNDS OF ORGANIZATION. 63 



3. Fibrin. This substance is usually procured for exa- 

 mination, from blood or muscle. From the former it is 

 obtained, by repeatedly washing the coagulated part which 

 appears after blood drawn from an animal has been allowed 

 to rest, until the water ceases to extract any thing soluble ; 

 that which remains is the fibrin. Muscle yields this sub- 

 stance after repeated macerations in water, the mass being 

 frequently subjected to pressure, in order to expel the 

 blood and other fluids from the pores. 



Fibrin is of a white colour, and soft and elastic, previous 

 to its being dried. It powerfully resists putrefaction, and 

 may be kept under water for a great length of time, with- 

 out undergoing any change. It is insoluble in cold water. 

 In boiling water, it curls up, and, after the ebullition has 

 ceased some hours, the water acquires a milky hue. A 

 portion of the fibrin has been dissolved, which produces, 

 by the addition of tannin, a precipitate of white flocculi. 

 Strong alcohol and ether partially decompose it, converting 

 it into an adipocirous matter. 



Acids dissolve fibrin directly, or alter its nature so as to 

 render it soluble in boiling water. Acetic acid dissolves 

 it entirely, and the solution has the appearance of jelly. 

 With the alkalies, fibrin readily combines, and, according 

 to BEKZELIUS *, the compound bears no resemblance to 

 soap. From the alkaline solution, the fibrin is thrown 

 down in a more or less altered state by the addition of 

 acids. 



When exposed to the destructive distillation, it curls up, 

 icn melts, gives out water, carbonate of ammonia, acetic 

 and carbonic acids, a fetid oil, and carburetted hydrogen 

 gas, indicating the presence of nearly the same ingredients 



enter into the composition of albumen. The charcoal 



Annals of Phil. ii. p. 23. 



