138 Dr. Buchanan <m the Fibrin contained in the Animal Fluids. 



sinus, rather than to the lymph from the lymphatic vessels. Such a 

 sinus might readily form after a wound, and would secrete a fluid 

 which, in its first stage, would have all the characters of coagulable 

 lymph ascribed to it — while our knowledge of the pathological pro- 

 cesses that take place in divided vessels, whether blood-vessels or 

 lymph-vessels, is contrary to the supposition that these vessels should 

 continue with patent orifices, after the rest of the wound had closed, 

 pouring out their natural contents. Nothing short of the injection of 

 the lymph-vessels after death, and the demonstration of their open 

 mouths, could establish so improbable a supposition. 



VII. — BLOOD. 



1. Contains transparent fibrin, and red globules. --^It is well known 

 that blood soon after being drawn coagulates, and thereafter sepa- 

 rates into two parts, the coagulum or solid part, and the serum or 

 liquid part. The coagulum consists chiefly of the red blood cor- 

 puscles, but it is universally acknowledged to contain also a portion 

 of colourless fibrin to which the coagulated mass chiefly owes its 

 tenacity. What are the grounds on which this opinion rests ? In the 

 first place, as the lymph is continually pouring into the blood from 

 the thoracic duct, the colourless fibrin which the lymph is known to 

 contain must be introduced into the blood. In the second place, in 

 cases of inflammatory disease, and certain other circumstances, the 

 transparent fibrin coagulates separately from the red corpuscles, the 

 latter constituting the lower portion of the coagulated mass, while the 

 former constitutes the upper layer, commonly called the bufFy coat of 

 the blood. It may, however, be objected that this is a phenomenon of 

 disease, and that we must show the blood to be similarly constituted in 

 the healthy state. The most conclusive argument then in behalf of the 

 opinion in question is derived from the phenomena observed when 

 liquid blood, as it flows from the arm, is mingled with about eight 

 volumes of serum of blood, when the red corpuscles fall to the bottom, 

 forming a dense layer, and the transparent portion, much more volu- 

 minous, occupies the upper part. The same phenomena are seen in a 

 still more beautiful and convincing form, when the transparent fibrin 

 is separated by the filter in a state of perfect purity. I have repeatedly 

 obtained it in this form, although I regret to be obliged to add, that 

 the experiment much more frequently fails than succeeds, and that I 

 have been quite unable to determine on what circumstances the suc- 

 cess or failure depends. 



2. Transparent fibrin generally held to exist in solution in the 

 serum of the blood. — In what state does the transparent fibrin exist 

 in the circulating blood ? The generally received opinion is that it 

 exists in a state of solution in the serum, the two together constituting 

 what has been named of late years '*the liquor sanguinis;'" and that 

 the fibrin only passes to the solid state after the blood is drawn, during 



