PROBLEMS OF MODERN SCIENCE 



Leading into the capillary area for the total 

 number of capillaries makes a very big area are 

 a number of little vessels called arterioles. These 

 arterioles are like taps that can be turned on or off, 

 or made to trickle slowly or to flow fast, and the 

 size of these orifices that lead into the capillary 

 area can be varied because certain nerves act upon 

 them. 



In some of these cases of shock it has been 

 found, then, that, owing to the nervous upset, an 

 undue flooding of the capillary area is produced. 

 It has further been found, in cases where such 

 nervous upset is negligible, that the capillaries are 

 themselves contractile. They can accommodate 

 more or less blood, because they sometimes become 

 narrower, sometimes wider, and the normal con- 

 dition of the capillaries that produces an efficient 

 circulation is due, no doubt, to certain chemical 

 materials, and possibly also to certain nerves 

 analogous to those I mentioned as controlling the 

 arterioles. It has again been found, in these cases 

 of shock, that the almost universal accompaniment 

 of the condition is crushed tissue muscle or flesh. 

 Crushed tissue becomes the ready prey of bacteria. 

 The material becomes broken down by the bacteria 

 and poisonous products result, and in many of these 

 cases there is the production of a certain poison 

 called histamine that brings about this particular 

 effect. You can produce the condition of shock 

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