ORGANIZABLE PRINCIPLES. 415 



properties are widely different: according to Dumas, however, there is a 

 marked difference in composition between Fibrin and the various forms of 

 Albumen, the former having less Carbon, and more Nitrogen, than the latter. 

 The following are the results of his analyses. 



From serum. From egs:s. 



Carbon 58-32 53-37 53-50 52-78 



Hydrogen 7-29 7-10 7-05 <HH> 



Nitrogen 15-70 15-77 15-77 10-78 



Oxygen ~) 



Sulphur I 23-69 23-76 23-68 21-48 



Phosphorus . . . .J 



100-00 100-00 100-00 100-00 



It is not, perhaps, of any great moment whether this difference has a real 

 existence or not ; for the conversion of Albumen into Fibrin is unquestionably 

 a process much more of vital than of chemical transformation. We shall 

 presently see, that Fibrin may be regarded as Albumen in which the process 

 of Organization has begun ; its molecules being ready to assume the peculiar 

 arrangement that is so designated : this arrangement takes place most com- 

 pletely, when the fibrinous mass is in contact with a living tissue, and is, 

 therefore, to a certain degree, under its influence. Fibrin, like albumen, may 

 exist in a soluble or in a coagulated state ; its soluble form only occurs, 

 however, in the living Animal Fluids, the chyle, lymph, and blood ; and 

 it seems to be the intermediate condition between the soluble albumen, and the 

 solid organized substances which are formed from it. When withdrawn from 

 the blood-vessels, the Blood soon coagulates (as do also the Chyle and Lymph, 

 when they contain sufficient fibrin, 564 and 565) ; and this coagulation is 

 entirely due to a change in the condition of the Fibrin, the particles of which 

 have a tendency to aggregation. The Fibrin may be obtained in a separate 

 form, by stirring fresh-drawn blood with a stick, to which it adheres in threads ; 

 these contain some fatty matter which is to be washed out with alcohol. In 

 this condition it possesses the softness and elasticity which characterize 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 then becomes a hard and brittle 

 substance ; but, like flesh, it imbibes water again when moistened, and recovers 

 its original softness and elasticity. When burned, it always leaves, like albu- 

 men, a portion of phosphate of lime. Fibrin is insoluble in alcohol and ether, 

 and also, under ordinary circumstances, in water; but when long boiled in 

 water, especially under pressure, its nature is altered, and it becomes soluble. 

 This is also the case with coagulated albumen. Fibrin, like albumen, unites 

 with acids as a base, forming definite compounds ; and with bases as an acid. 

 Its correspondence with albumen has been recently proved by the fact (first 

 stated by M. Denis), that it may be entirely dissolved in a solution of nitrate 

 of potash ; and that this solution is coagulated by heat, and greatly resembles 

 a solution of albumen. This is only true, however, of the ordinary Fibrin of 

 Venous blood ; for that which is obtained from arterial blood or from the buffy 

 coat, or which has been exposed for some time to the air, is not thus soluble. 

 This is an important and interesting circumstance. The difference appears 

 to depend upon the larger quantity of oxygen contained in the latter ; for a 

 solution of Venous Fibrin in nitre, contained in a deep cylindrical jar, allows 

 a precipitate in fine flocks to fall gradually, provided the air have access to 

 the surface, but not if it be prevented from coming in contact with the fluid ; 



