472 MATERIA MEDIC A AND THERAPEUTICS. 



the general muscular paralysis, which is another result of the 

 cerebral anaemia ; and the patient falls. The recumbency fortu- 

 nately has a favourable effect : it restores the circulation through 

 the cardiac and vaso-motor centres, increasing their activity ; 

 and renders the cerebral centres more responsive to afferent 

 impressions. 



IV. NATURAL RECOVERY. 



The -whole circulatory system is furnished with so many and 

 so accurate regulating and .compensating mechanisms, that not 

 only the great range of normal conditions to which it is exposed, 

 but even many morbid changes, can be successfully met. The 

 chief of these provisions for preventing or counteracting disease 

 are the reserve force of the heart ; the power of compensatory 

 hypertrophy ; the depressor mechanism ; the arrangements for 

 relief of the vessels by escape of the fluid portions of the blood 

 through the kidneys and bowels, and into serous spaces ; and 

 the natural mode of recovery from haemorrhage and syncope. 

 All these methods of natural relief or recovery are full of sugges- 

 tions- to the therapeutist, and rational treatment must follow 

 nature's lines. The two circumstances which chiefly set a limit 

 to compensation are failure of the coronary arteries to supply 

 the hypertrophied walls, and suddenness of the cardiac lesion, 

 which may hopelessly disturb the circulation before there is 

 time for hypertrophy to occur. 



V. THERAPEUTICS. 



Although the details contained in the four preceding sections 

 are very numerous and complex, the rational therapeutics of 

 the diseases of the heart and vessels can be sufficiently illustrated 

 by a few simple principles. The grand fact that stands out 

 prominently amongst all the others is that dilatation must be 

 prevented or relieved. It is a purely physical effect or state, 

 resulting from the failure of the great physiological condition on 

 which alone the circulation can be and is carried on, namely, 

 that the driving power must always be greater than the resistance, 

 i.e. whilst it varies with it, it must never fall below it. There 

 are many other indications for treatment, but none that approach 

 this in importance. 



The general treatment of disorder and disease of the heart 

 will mainly consist in ensuring an equable manner of life. 

 Extraordinary influences of every kind, bodily and mental, 

 especially exertion and excitement, must be shunned by persons 

 suffering from cardiac disease, or in whom any of its common 

 causes may be at work. When disease attacks the valves 

 (endocarditis), e.g. in acute rheumatism, absolute bodily rest 



