524 MATERIA MEDICA AND THERAPEUTICS. 



Lastly, the modus operand* of certain anhidrotics is still 

 doubtful, and their employment so far empirical, e.g. Zinc, 

 Quinia, and Opium under particular circumstances. It is 

 possible, however, that these and other measures control the 

 pathological cause of the sweats, in a manner to be afterwards 

 indicated. 



4. Other Channels of Loss of Heat. The kidneys and the 

 bowels afford us a direct means of reducing the temperature of 

 the body by the abstraction of an increased amount of warm 

 excretions, in the form of urine and watery motions. In the 

 case of the bowels the effect is decidedly assisted by the reflex 

 dilatation of the cutaneous vessels which accompanies purgation, 

 as described in chapter vi. 



o. The Heat-forming Tissues. In discussing metabolism in 

 chapter ix., we found that we possess the power of diminish- 

 ing tissue change, and the production of heat, by various 

 means. Here we shall refer only to certain drugs which 

 possess this action. We call these antipyretics (avrl, against, 

 Trt/perbs, fever). The most powerful of these is Cinchona 

 (Quinia), which interferes with metabolism generally, lessens the 

 amount of heat produced, diminishes the excretions, and spares 

 the organs. Salicin and Salicylic Acid, "Resorcin, Chinolin, 

 and Kairin, have a similar but less powerful action. Whilst 

 these drugs distinctly reduce or spare the activity of the tissues, 

 they have but little influence in reducing the temperature of 

 healthy individuals, this effect probably being prevented by the 

 ordinary mechanisms of regulation. Alcohol also diminishes 

 tissue waste, apparently in a different way from Quinia, viz. 

 by being itself decomposed in the tissues with great readiness, 

 thus sparing the organs. Even an increased amount of heat is 

 generated in the tissues by the oxydation of Alcohol, but so 

 greatly does it stimulate refrigeration, as we have seen, that its 

 total effect on the organism is antipyretic. The Aromatic sub- 

 stances have a less powerful influence in diminishing metabo- 

 lism. Possibly, Digitalis, Aconite, and Veratria, have also an 

 antipyretic effect, like Alcohol, but their mode of action is 

 obscure, unless it occur entirely through the circulation, as has 

 been already suggested. 



III. PATHOLOGICAL RELATIONS. 



The mechanism concerned in the regulation of the body- 

 heat is liable to disorder, when heat-forming or heat-losing 

 organs are diseased. Elevation of the body temperature, or 

 pyrexia, most commonly called fever, is very rarely absent 

 in illness of any consequence. An abnormal fall is seen as 

 an effect of extreme cold or of exhausting diseases, but being 



