84 GENERAL THERAPEUTICS FOR VETERINARIANS 



rule, cannot be used. Simple washing or douching with cold 

 water, also wrapping in cold wet sheets, is without considerable 

 value. 



MEDICAL ANTIPYRETICS 



Synonyms: Antifebrilica, antithermics, febrifuges, antitypics, anti- 

 typosics, antiperiodics. 



Actions. — The reduction of temperature by antipyretics is 

 brought about in very different ways. The action of most of them 

 is very complicated. According to the mode of action, they may 

 be divided into the following groups: 



1. Depression of the heat centre in the brain, when it is excited 

 by fever, with consequent reduction of temperature, appears to be 

 the dominant action of the modern antipyretics: antipyrine, 

 acetanilid, aspirin, phenacetin, salipyrin, lactophenin, pyramidon, 

 etc. They are to be regarded accordingly as narcotics for the heat 

 centre (or the vasomotor centre ?). This property is in agreement 

 with the fact that antipyrine, aspirin, etc., also exert a narcotic 

 effect upon other parts of the nervous system, especially in neu- 

 ralgia and also in the production of local narcosis; the temper- 

 ature also falls in morphine and chloroform narcosis. The rapid 

 action of the modern antip3Tetics is in great contrast to that of the 

 other antipyretics, the fall of temperature beginning as early as 

 10 to 20 minutes after administration, and can only be explained 

 through the action of a promptly functionating heat-regulating 

 centre. Digitalis, the action of which is essentially different, does 

 not reduce temperature until the twelfth to the twenty-fourth 

 hour. The action of the modern antipyretics upon the calorific 

 centre may be demonstrated experimentally. Given to animals 

 with fever resulting from septic infection, antipyrine immediately 

 reduces the temperature so long as the heat centre remains intact. 

 After section of the brain back of the corpus striatum, however, 

 antipyrine has no influence on the temperature. 



2. Increasing heat dissipation through the skin. Those anti- 

 pyretics which by stimulating the vagus centre increase blood- 

 pressure and which by regulating the distribution of the blood 



