AND BLOOD PRESSURE 173 



effect of poultices and stimulating solutions lies in the hyperaemia 

 and greater flow of plasma which they produce. The old ideas 

 underlying the words " derivants " and " revulsants " are entirely 

 wrong. Mustard poultices and turpentine stoups do not draw 

 the blood from the deeper diseased parts into the superficial, 

 but produce hypereemia of both. The abdominal organs are ren- 

 dered hyperaemic by exposing the abdomen to a hot air bath. 

 The intra-pleural temperature may be raised slightly (owing to 

 hyperaemia) by applying an irritant to the skin of the chest, and 

 may be raised several degrees by applying hot poultices. The 

 greater warmth of the part not only induces hyperaemia but in- 

 creases phagocytic and other actions. Herein we find the explana- 

 tion of the success of these old-fashioned remedies in the treatment 

 of fevers and inflammation. Bleeding likewise may have been 

 effectual by drawing tissue lymph into the blood and so increasing 

 the stock of bactericidal and opsonic substances. It is unlikely 

 that our forefathers bled fever-patients for nothing excepting 

 the fee. 



SHOCK AND COLLAPSE 



When a large hutch rabbit is held for a few minutes in the 

 vertical position with its limbs stretched out and head uppermost, 

 it may become unconscious and die from cerebral anaemia. The 

 blood collects in the large flaccid abdomen, the animal not being 

 able to return it to the heart by changing its posture. It struggles 

 to maintain a circulation cerebral anaemia excites convulsions 

 which squeeze the blood from the limbs, &c., into the heart but the 

 difficulty in face of the circulation is too great and the animal dies. 

 A wild rabbit with taut abdomen is not affected in this way, neither 

 is a cat or dog, but a goat is with its capacious belly. The wild 

 rabbit can, however, be brought into like state by a dose of chloral, 

 and so can the dog by chloroform poisoning or by bleeding. The 

 emotional fainting of a man is due to the inhibition of the nervous 

 system a neutralisation of all other afferent stimuli by one all- 

 powerful one the consequent sudden relaxation of muscular tone, 

 collapse of the body and non-return of venous blood to the heart. 

 The horizontal posture or compression of the abdomen immediately 

 restores from syncope the rabbit or the man. The condition of 

 shock which results from division of the spinal cord in the lower 

 crrvical region is recovered from and cannot be renewed by 



