THE FLUIDS OF THE BODY 71 



The bloodvessels contract. A clot has time to form. An 

 emotional tendency to faint at the sight of blood is a provision 

 for giving the various causes which stop bleeding an opportunity 

 of coming into play. It is a useful reflex action, always sup- 

 posing that the person who is liable to it faints at the sight of 

 his own blood. Amongst other reasons for the greater fortitude 

 of women they are far less subject to this emotional reflex 

 than men might be alleged the circumstances of life of primi- 

 tive people. It was the part of their women-folk to dress 

 wounds, not to receive them. 



The phenomenon of coagulation has attracted attention 

 from the earliest times. It was a phenomenon that needed 

 explanation, and culinary experience suggested analogies close 

 at hand. Hippocrates attributed the clotting of blood to its 

 coming to rest and growing cold. The blood which gushed 

 from a warrior's wound formed a still pool by his side. It set 

 into a jelly as it cooled. Until the second quarter of the nine- 

 teenth century this theory was deemed sufficient. It then 

 occurred to two men of inquiring mind to institute control 

 experiments. John Davy placed a dish of blood upon the hob. 

 William Hunter kept one shaking. In both experiments the 

 blood clotted more quickly than it did in vessels of the same 

 size, containing the same amount of the same blood, left upon 

 the table. 



Even before this date an observation had been made regard- 

 ing the circumstances in which clotting occurs, which has thrown 

 much light upon the causes of the phenomenon. In 1772 

 Hewson gently tied a vein in two places. At the end of a couple 

 of hours he opened the vein. The blood was still liquid, but 

 clotted in a normal manner after it was shed. Scudamore 

 showed that blood clots more slowly in a closed than in an 

 open flask. A new theory, as little trustworthy as Hippo- 

 crates', was based upon these observations. Blood clotted 

 because it was exposed to air. A record of all observations of the 

 circumstances of coagulation, and of all the theories to which 

 they have given rise, would make an exceptionally interesting 

 chapter in the history of human thought. It would bring into 

 singular prominence stages in the development of what is now 

 known as the " scientific method." Not that Science has a 

 method of her own. Philosophers of all classes would follow 



