LESSON 21.] COMPOUNDS OF THE ANIMAL BODY. 61 



and alcohol, and decomposes by heat without fusing : this substance 

 has been called Proteine, from an idea that it is the first and funda- 

 mental principle of which Albumen, Fibrine, &c., are but modifica- 

 tions. It contains the same proportions of Carbon, Hydrogen, Oxy- 

 gen, and Nitrogen, as Albumen and Fibrine ; but it is destitute of 

 Sulphur and Phosphorus; Liebig, however, doubts the latter as- 

 sertion. 



358. Albumen shows no tendency to coagulate, except by the aid 

 of chemical influences, and its coagulum is devoid of structure. 

 Fibrine exhibits a constant tendency to form solid tissues, and it 

 appears only to be kept in check by the operation of influences not 

 understood. It is highly probable that the production of tumors, 

 and morbid growths, in the interior of the body, no less than upon 

 its external surface, owe their origin to the persevering tendency of 

 Fibrine to form tissues ; exhibited at a period when the law (what- 

 ever it may be) that should govern it, is in abeyance. Certain it is 

 that a great number of adventitious (accidental, extrinsic) growths 

 when microscopically examined, consist only of fibrillated fibrine. 



359. The conversion of Albumen into Fibrine may be regarded 

 as the first great step in the process of nutrition ; the mode by 

 which the varied materials used for food, are made to form a part of 

 the tissues of the living body. 



360. Fibrine first makes its appearance in the Chyle the fluid 

 found in the Lacteals (lacta, milk) ; Chyle is the immediate product 

 of digestion, and will be more fully explained hereafter. 



361. The proportion of Fibrine in the blood, as indicated by the 

 firmness of its coagulum, is much greater than that contained in the 

 Chyle, and in certain conditions of the blood, resulting from disease, 

 the proportion of fibrine is increased to twice, thrice, or even four 

 times its usual amount. 



362. In the process by which injuries to parts are repaired, there 

 is an exudation of fibrine ; this is said to form plastic, or coagulable 

 lymph. 



363. In exudation, the liquor sanguinis (fluid portion of the 

 blood) is alone poured out, and this fluid holds the fibrine in solu- 

 tion ; the solid portion (red corpuscles) takes no share in this process 

 of reparation. 



364. When describing the latex in plants, a comparison was in- 

 stituted between its properties and the properties of the blood in ani- 

 mals, particularly in relation to its ability to form tissues by a process 

 of coagulation. 



