186 Prof. Draper on the Cause of the 



difficulty in understanding the cause of the false importance 

 which has been attached to the fact of its coagulation. When 

 we also remember that the phenomenon is one which, far 

 from taking effect instantaneously, requires a considerable 

 length of time, and estimate duly the demand that is made for 

 fibrine by the system upon the blood, we shall have no dif- 

 ficulty in perceiving the truth of the observation which I thus 

 wish to bring into a clear point of view, — that the tendency 

 to coagulation in the system is as great as it is out of it, and 

 that the true difference in the two cases is, that in the former 

 the resulting solid is taken up and appropriated to the wants 

 of the oeconomy; in the latter it remains undisposed of, and, 

 entangling the blood-discs in its meshes, produces a volumi- 

 nous and therefore deceptive clot. 



It is with this matter of the coagulation of blood precisely 

 as it was formerly with putrefaction. Many of the older phy- 

 siologists defined a living body as a mechanism having the 

 quality of resisting external changes. After death its parts 

 were ultimately resolved into water, ammonia, and carbonic 

 acid. But better views on these topics are now entertained, 

 and we know that the living body undergoes these putrefactive 

 changes just as much as the dead, but then in it there are 

 appointed routes by which the resulting bodies may escape; 

 the carbonic acid through the lungs, the nitrogenized com- 

 pounds through the kidneys, the water through both these 

 organs and the skin. It is in this as in the coagulation of the 

 blood, there is no difference in the chemical changes taking 

 place, the difference consists in the disposal finally made of 

 the resulting products. 



That coagulation tends to take place equally in the living 

 system as out of it, there is abundant proof. What are all 

 the muscular tissues which constitute by far the larger portion 

 of the soft parts, but fibrine which has thus been separated 

 from the blood ? And those muscular tissues every moment 

 are wasting away, and giving origin to the metamorphosed 

 products that we find escaping from the lungs, the kidneys, 

 the liver ; from what source then do they repair their waste, 

 if not from fibrine coagulated from the blood during the act 

 of life? Every muscular fibre is a living witness against the 

 doctrine that it is death that brings on the coagulation of the 

 blood. 



That the truth of this view, which at first sight may appear 

 indefensible, may be more clearly made out, let us consider 

 under what circumstances the blood is placed whilst moving 

 in the system. We have to remember that coagulation is not 

 an instantaneous phenomenon, but one which requires a con- 



