CHAPTER III. 



COAGULATION OF THE BLOOD. 



General considerations Characters of the clot Characters of the serum Coagu- 

 lating principle in the blood Circumstances which modify coagulation Co- 

 agulation of the blood in the organism Spontaneous arrest of hemorrhage 

 Cause of coagulation of the blood Summary of the properties and functions 

 of the blood. 



THE remarkable property in the blood of spontaneous 

 coagulation has been commonly recognized as far back as 

 we can look into the history of physiology ; and since the 

 immortal discovery of Harvey, which naturally gave an im- 

 pulse to investigations into the properties of the circulating 

 fluid, there have been few subjects connected with the physi- 

 ology of the blood which have excited more universal interest. 

 At first, the ideas with regard to the cause of this phenom- 

 enon were entirely speculative. The first definite experi- 

 ments on record were performed by Malpighi and published 

 in 1666. He was followed by Borelli, Ruysch, and a host of 

 others who hold conspicuous places in the history of our 

 science ; among whom may be mentioned Hunter, Hewson, 

 Miiller, Thackrah, J. Davy, Magendie, Nasse, and Dumas. 

 "While much labor has been expended on this subject, the final 

 cause of coagulation cannot even now be said to be settled 

 beyond question. 



The blood retains its fluidity while it remains in the 

 vessels, and circulation is not interfered with. It is then com- 



