PATHOLOGY OF FAINTING. 403 



them ill the same way that rooms are warmed by hot- water 

 pipes, and whenever the circulation ceases there is nothing 

 to prevent the surface of the body being cooled down to the 

 temperature of the surrounding medium, and such, in fact, does 

 take place. The lividity or blueness which is occasionally 

 observed is due to the blood in the capillaries becoming dark 

 and venous as it flows sluggishly through them, or even stag- 

 nates in them altogether when the circulation is very weak. I 

 shall at present say nothing about the respiration or sickness, 

 but pass on to consider the insensibility which we find in 

 syncope though not in shock, and which distinguishes the 

 former from the latter. 



The functions of the brain, on whose failure insensibility 

 depends, require for their performance a constant supply of 

 blood, and when this is cut off they at once cease. A year or 

 two ago Dr. Waller proposed to produce temporary anaesthesia 

 for short operations by compressing both carotids, or, in fact, 

 garotting the patient ; and I have been informed by my friend 

 Mr. Image, of Bury St. Edmunds, that in Baron Larrey's 

 Hopital du gros Caillou, in Paris, it was the usual custom, before 

 the introduction of chloroform, to lay a patient on his back and 

 then to lift him up very suddenly to the standing posture, when- 

 ever they wished to induce fainting for the purpose of relaxing 

 muscles in cases of dislocation. The vessels of the patient were 

 carrying on the circulation all right while he was in the hori- 

 zontal position, but they had not time to adapt themselves to 

 the altered conditions when the man was placed upright, and so 

 the blood ran to the depending parts of the body, and the brain 

 was left without it. 



But why should a fainting fit, which, apparently, is more 

 severe than shod:, inasmuch as the brain also has ceased to act, 

 and the patient is thus rendered more deathlike, be quickly 

 recovered from, while shock lasts for many hours ? This is a 

 question difficult to answer, inasmuch as the necessary data fail, 

 and we are forced to fall back on hypothesis. In attempting to 

 answer it we must remember that it is not really the heart's 

 action which keeps up the circulation directly. It is the 

 pressure of the blood inside the arteries forcing it on through 



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