

FIBRILLATION OF FIBRINE. 93 



from its meshes, and rises on the surface, while the corpuscles (co- 

 lored and colorless) remain inclosed in the coagulum. Sometimes 

 the coagulum is not fully contracted under forty to forty-eight 

 hours. When the fibrine is left separate from all other elements, 

 its threads or fibrils alone occupy the field of vision, and afibrd a 

 striking resemblance to the membrane lining the egg-shell. (Fig. 48.) 



III. Coagulation is fibrillation, and is to be regarded as a vital 

 act, since it is organization, though perhaps of the lowest kind. 

 But fibrillation is the last and the highest vital act of the fibrine. 

 The more highly vitalized, therefore, the fibrine, the slower and the 

 more perfect the fibrillation. Hence, as it would seem, inflamma- 

 tory blood both coagulates most slowly, and affords the most com- 

 plete fibrillation. Indeed, the solidification is so long retarded (ten 

 to twenty minutes), that the corpuscles the heaviest portion of the 

 blood have time to subside, and thus leave the upper portion of the 

 clot of a light straw color ; and which has given to the coagulum, 

 in such cases, the name of the "buffy coat." This is characteristic 

 of inflammation, however, only when due to slow coagulation. It 

 occurs, also, in anaemia and chlorosis ; the coagulation being rapid 

 in these conditions, but the red corpuscles in the blood being so 

 deficient as not to give the usual bright red color to the coagulum. 



IV. The fibrillation of fibrine is the more perfect in all the fol- 

 lowing conditions: 



1. When its vitality is apparently highest, as in inflammation ; 

 when also coagulation is most slowly performed. 



2. When it is most nearly isolated from the other elements of 

 the blood, especially the corpuscles, as in inflammatory exudations, 

 which consist of fibrine and serum only in all cases except when 

 hemorrhage also has occurred. 



3. When its contact is most perfect with the living tissues, as in case 

 of inflammatory exudations upon serous membranes, when the ex- 

 udation is, of course, in contact with the tissues on loth its surfaces. 

 In case of inflammation on mucous membranes, or the skin, the 

 exudation can be in contact only on one surface, except in the 

 rectum, vagina, &c. Hence false membranes, so called, which are 

 originally mere fibrillated fibrine, are more common on serous sur- 

 faces, and very uncommon on mucous membranes, except those 

 just mentioned. 



4. When it is at perfect rest after leaving the bloodvessels. Here, 

 again, a serous membrane has the advantage. In pleurisy and peri- 



