FIBRIN. 489 



and broken-up sweet almonds), are freed of most of 

 their oil by pressure, and then boiled for a short time 

 with water, most of the legumin, in addition to sugar 

 and gum, is dissolved and can be reprecipitated by 

 acetic acid ; the albumen, however, remains behind 

 coagulated. Or, if the last particles of fatty oil are 

 extracted from the pressed sweet almonds by means of 

 ether, and they are then treated with cold water, legu- 

 min and albumen are dissolved. If the solution is 

 now heated to boiling, the albumen is thrown down in 

 a coagulated condition, and the legumin can afterward 

 or also previously be precipitated with acetic acid. In 

 addition to this, another protein compound, emulsin, is 

 contained in sweet almonds. This compound appears 

 to be different from those described, and is character- 

 ized by its peculiar action 011 amygdalin and salicin 

 (pp. 412 and 414). 



4. Fibrin. Only known in the insoluble condition. 

 Separates spontaneously from the blood, a short time 

 after the latter has left the living organism, and forms 

 the principal part of the blood-clot. It is not con- 

 tained in circulating blood, but is formed after this 

 has left the body, by the union of two albuminoid 

 substances contained in blood and other animal fluids, 

 viz: fibrinogenous and fibrino-plastic substance. The 

 fibrino-plastic substance (paraglobuliri) is obtained 

 from blood-serum, by carefully adding acetic acid to 

 serum diluted to twenty times its volume, or better 

 by conducting carbonic anhydride into the diluted 

 solution, and then washing the precipitate with water. 

 The fibrinogenous substance can be prepared in the same 

 manner from the pericardium-fluid of the cow, or the 

 fluid of hydrocele. Both of these protein compounds 

 are insoluble in water, and in a saturated solution of 

 common salt ; soluble in a dilute solution of common 

 salt, and in very dilute hydrochloric acid. When one of 

 these substances is dissolved in a dilute solution of sodi- 

 um chloride and an equal amount of the other substance 

 is added in a moist condition, the whole mass coagu- 

 lates after a time, forming fibrin. Fibrin is a grayish- 



