PHYSIOLOGY 



physiologists have devoted a considerable amount 

 of attention to the capillary circulation. It is 

 because, as I said, it is the part of the circulation 

 where the blood actually performs its duty. The 

 flow along the other vessels is merely a means to 

 an end ; the main thing is the distribution of the 

 blood as it flows along these microscopic vessels. 



I have alluded to the question of shock as being 

 due to loss of blood. It was found during the 

 War that there were many cases of shock in which 

 there was comparatively little loss of blood. Shock 

 has been divided into various categories. There 

 is ' shell-shock/ due to injury to, or a thorough 

 shaking up of, the brain (concussion). That is not 

 the shock which I am speaking about. There is 

 ' primary shock,' in which the person is knocked 

 ' all of a heap ' as the result of a sudden injury ; 

 and there is what I want more particularly to dwell 

 upon, viz., ' secondary shock,' in which the person, 

 after the immediate effects of the wound have 

 passed away, goes back into a condition of collapse, 

 although he may have lost very little blood. Where 

 has the blood gone to ? It is found that it has 

 dilated the capillaries, and has become stagnant 

 there. It has got side-tracked in certain parts 

 of the body, so that not so much is available for 

 the more important organs, which, on account 

 of their comparatively bloodless condition, become 

 inactive and may cease work altogether. 



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