Dr. Buchanan on the Coagulation of the Blood. 21 



a white solid mass, such as we often see of smaller size on inflamed 

 membranes, and in the interior of the eye. 



These various experiments fully satisfied me that the tissues possess 

 the property of coagulating fibrin : and I was farther disposed to think, 

 that this power was most energetic in the primary cells or vesicles ; 

 and less energetic as these cells passed into secondary forms, as in the 

 red corpuscles of the blood, the pus globules, and the various tissues 

 of the body. This corresponds well with the greater vigour of 

 development in foetal life and infancy, when the tissues have deviated 

 little from their primary structure ; and the gradual diminution of the 

 activity of the function as life advances, and the tissues are more and 

 more altered. The coagulation of the fibrin of the effused liquor 

 sanguinis, under the influence of the primary cells and tissues, may 

 probably, therefore, be regarded as the primary organizative act by 

 which the assimilable matter dissolved in the nutritious liquid passes 

 into the form of an organized solid. There are, however, two distinct 

 forms under which this act presents itself to our observation. In the 

 one, which is that which occurs in normal circumstances in the living 

 body, the process takes place slowly, and the product consists of isola- 

 ted granules, which are gradually developed into perfect cells: in the 

 other, which occurs in the effused fibriniferous liquids, the process is 

 sudden, and the product a gelatinous mass. It is to the latter that 

 the name of coagulation peculiarly belongs, and it is to be regarded 

 rather as a pathological action than as belonging to the domain of 

 physiology. The two processes may be aptly compared to the deposi- 

 tions which take place from saline solutions ; if the deposition take 

 place slowly the product consists of regular crystals, but if rapidly, it 

 is an amorphous mass. 



It is scarcely necessary for me to add, that I am now satisfied, that 

 the fibrin of the animal fluids exists in them in solution, previous to 

 its appearing in a corpuscular form: and that the liquor sanguinis 

 differs from the serum which separates from the blood-coagulum in 

 this respect, that the former contains fibrin in solution, while the latter 

 has been defibrinized by the action of the colourless blood-corpuscles 

 upon it I also think the theory of the production of cell-germs and 

 cells by the reaction of the two kinds of serum upon each other, less 

 probable than the theory of their formation stated above. The same 

 theory may also be applied to explain the origin of the blood-corpuscles 

 in the capillary lymphatics, and the production of the numerous less 

 regular corpuscles which are formed in the capillary blood-vessels 

 during inflammation, and which, after mingling with the circulating 

 blood, rise to its surface when drawn, and reacting on the fibrin 

 occasion the buffy coat of tho blood. The opinion expressed by Dr. 

 Anderson in his paper alroady quoted, that the blister-liquid contains 

 fibrin which is precipitated during coagulation, I believe to be correct 

 in many cases, as I have sometimes found that liquid, when acted upon 



