106 ON THE ELEMENTARY PARTS OF THE HUMAN FABRIC. 



C. H. IT. O. 



Protid 13 914 



Erythroproticl ....... 13 15 



Gelatine 13 10 2 5 



Besides these substances and Ammonia, Formic and Carbonic Acids are produced by the 

 decomposition of Proteine with potash ; the acids unite with the potash, whilst the ammonia 

 is set free. 



117. It is very important, however, to bear in mind, that however close 

 may be the chemical approximation between Albumen and Fibrine, there is a 

 wide difference between them, as regards their relations to living organized 

 structures : and this difference is one of which chemistry takes no cogni- 

 zance. To use a rather homely illustration, the relation between Albumen, 

 Fibrine, and Organized Tissue is somewhat of the same nature as that which 

 exists between the raw cotton, the spun yarn, and the woven fabric. Albu- 

 men shows no tendency to coagulate, except under the influence of purely 

 chemical agents, and its coagulum is entirely destitute of structure, being a 

 mere homogeneous aggregation of particles. On the other hand, Fibrine 

 exhibits a constant tendency to pass into the form of a solid tissue ; and it 

 seerns only restrained from doing so by certain influences, whose nature is 

 not understood, to which it is subjecte'd whilst contained in the vessels of the 

 living body. The conversion of Albumen into Fibrine, therefore, is the first 

 great step in the process of Nutrition, by which the materials supplied by the 

 food are made to form part of the living tissues of the body ; and it is the one 

 to which the term Assimilation may be most appropriately applied. As 

 already mentioned, Albumen is always the starting-point ; since the fibrinous 

 elements of organized tissues are reduced, by the solvent power of the gas- 

 tric fluid, to the same form with the unorganized coagulum of the albumen of 

 the egg. The first appearance of Fibrine is in the Chyle, or fluid of the 

 Lacteals ; and when this is examined in the neighbourhood of the part where 

 it has been absorbed, the traces of Fibrine which it presents are very slight. 

 As the Chyle flows along the lacteals, however, the proportion of Fibrine in- 

 creases ; and it reaches its maximum at the point where the Chyle is de- 

 livered into the current of the circulating Blood. The proportion of Fibrine 

 in the Blood, as indicated by the firmness of the coagulum which it forms, is 

 much greater than that contained in the Chyle, notwithstanding that there is 

 a constant withdrawal of this element for the purpose of nutrition. And in 

 certain disordered states of the system, in which the formative powers of the 

 Blood are so exalted, as to produce a tendency to the formation of tissue in 

 abnormal situations, the proportion of Fibrine is found to be increased to 

 twice, thrice, or even four times its usual amount. And even where there is 

 no such general increase, a local increase is made evident in the large pro- 

 portion of fibrine, which exists in the exudations poured forth for the repara- 

 tion of injuries; these exudations, when possessed of a high formative pro- 

 perty (that is, a readiness to produce an organized tissue), are said to be 

 composed of plastic, or coagulable lymph; but this is nothing more than the 

 Liquor Sanguinis, or fluid portion of the Blood, holding in solution an unu- 

 sual quantity of Fibrine. It is evident, from these facts, that some peculiar 

 agency must exist within the vessels, by which the elaboration of the Fibrine 

 from the Albumen is effected ; and we shall hereafter endeavour to bring 

 together certain facts, which seem to indicate its nature. 



J18. The tissue that is produced by the apposition of the particles of 

 Fibrine, when left to themselves, and solely influenced by their own mutual 

 attraction, is of a very simple character, being composed of fibres interlaced 

 with each other in various directions. This arrangement can be seen in the 

 ordinary Crassamentum, or clot of healthy Blood, by examining thin slices 



