ALBUMINOUS COMPOUNDS. 113 



Cartilage, is distinguished as Ohondrine. This requires longer boiling 

 than gelatine for its solution in water ; but the solution fixes into a jelly 

 in cooling, and dries by evaporation into a glue that cannot be distinguished 

 from that of gelatine. Like gelatine, it is thrown down from its solution by 

 alcohol, creasote, tannic acid, and bichloride of mercury ; but it is also 

 precipitated by acetic acid, alum, acetate of lead, and protosulphate of 

 iron, which do not disturb a solution of gelatine. It is curious that, in 

 proportion as Cartilages become fibrous, their Chondrine gives place to 

 Gelatine ; and during the progress of ossification, the Chondrine seems- 

 to be entirely replaced by Gelatine, of which the fibrous basis of the' 

 bony tissue is composed. 



178. The foregoing may be considered as the chief among the " raw 

 materials" of the Animal fabric; and it is now to be shown, that while 

 the Gelatinous components merely become subservient to the formation 

 of tissues, whose structure is the simplest possible, and whose function 

 is purely mechanical, the destination of the Albuminous compounds is 

 much higher ; it being at the expense of the latter that those tissues are 

 generated, which are the instruments of the purely vital operations of 

 the Animal economy. In their progress towards the state of complete 

 organization, however, we find that they pass through an intermediate 

 condition, which is one that requires special consideration. The fluids that 

 are formed at the expense of the Albuminous matters which have been 

 digested -and absorbed, contain a substance, which is so closely related 

 to Albumen in its ultimate Chemical composition, as not to be distin- 

 guishable from it with any degree of certainty,* but which, though still 

 fluid whilst circulating in the living vessels, exhibits a decided tendency 

 to assume the organized form, and manifests properties which are so 

 different from those of inorganic matter, that they must be regarded as 

 vital. This substance is Fibrine. It is found in the Chyle, or crude 

 blood, soon after this is taken up from the food ; it presents itself in 

 gradually increasing proportion, as the Chyle slowly passes along the 

 Lacteal vessels, and through the Mesenteric glands, towards the termi- 

 nation of the Absorbent system in the Venous ; and it is also found in 

 the fluid contents of that other division of the Absorbent system, the 

 Lymphatics, which is distributed through the body at large, and which 

 seems to have for its chief office to take up, and to reintroduce into the 

 circulating current, such particles contained in the fluids of the tissues, 

 as do not require to be at once cast out of the body, but may be again 

 employed in the process of Nutrition. But it is found, above all, in the 

 Blood ; the fluid whose ceaseless and rapid course through the body sup- 

 plies to every element of the structure the materials of its growth and 



* According to some analyses, Fibrine differs slightly from Albumen in ultimate com- 

 position, the proportions x>f its several constituents in 1000 parts being as follows ; 

 Carbon 546, Hydrogen 70, Oxygen 220, Nitrogen 157, Sulphur 4, and Phosphorus 3. 

 The difference in their vital relations, however, is far greater than any such difference 

 in their chemical composition can account for, and can only be justly attributed to the 

 forces brought to act upon the fibrine during its circulation in the vessels of the living 

 body. It has been recently maintained, that Fibrine is not to be regarded (as here 

 represented) as Albumen in the transition-stage of incipient organization, but that it is 

 a product of the disintegration of the tissues, only received back into the blood in order 

 that it may be carried out of the system through the excretory channels. For a discus- 

 sion of this hypothesis, see the Brit, and For. Med. Chir. Review, vol. vii. pp. 153, 473. 



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