92 



IMMEDIATE PRINCIPLES OF THE TISSUES. 



duce to the nutrition of the permanent tissues, 1 and that it becomes 

 itself permanent only in persistent false membranes, and other simi- 

 lar pathological epigeneses. 



Fibrine is probably converted, in its final metamorphosis, into 

 urea, uric acid, and other effete substances, like albumen and the 

 proper tissues. 



Remarks. I. It is not probable that what is called fibrine is a 

 simple substance. It always contains salts, sulphur, and fat even 

 2.6 per cent, when dry. Besides, Lehmann remarks that it is 

 "wholly at variance with all preconceived ideas to attribute life to 

 a simple organic substance;" 2 and fibrine manifests a property 

 which can hardly be otherwise than vital, viz., spontaneous coagu- 



Fig. 43. 



II. Normally, the fibrine coagulates in human blood to such an 

 extent as to give the blood a gelatinized appearance in from two to 

 four minutes; in inflammation, this appearance is delayed ten to 

 fifteen minutes, or longer. In case of filtered frog's blood, or of 

 inflammatory exudations (the red corpuscles being in both of these 

 cases separated from the rest of the blood, so that no obstruction is 

 offered to the process or to the view), molecular granules are first 



seen in the clear fluid, at various 

 points, from which very fine 

 straight threads are next seen to 

 radiate. (Fig. 43.) The latter 

 do not, however, form star-like 

 masses like crystallization, but 

 they finally cross each other in 

 all directions, and inclose the 

 colorless corpuscles (if present), 

 so that they can hardly be dis- 

 tinguished in the network. As 

 coagulation occurs in ordinary 

 circumstances, the fibrine at 



first incloses all the other con- 

 Fibres in coagulating blood. 



stituents of the blood, and the 



whole mass of blood appears to have gelatinized. But the contrac- 

 tion of the fibrine becoming more advanced, the serum is squeezed 



1 See chapter on the " Histological Relations of the Blood.' 



2 Chemistry, vol. i. p. 313. 



