18 Transactions of the Royal Canadian Institute 



ishing success and for the most part without any voluntary guidance 

 on our part. The mere fact that the machinery runs so well through so 

 many years is a demonstration of the completeness of the physiological 

 adaptations. But the more one learns about the delicate mechanisms 

 and adjustments of the body the more he will be inclined to sympathize 

 with Stevenson's point of view founded on personal experience — "And 

 what, says he, pathologically looked at, is the human body with all its 

 organs, but a mere bagful of petards? The least of them is as dangerous 

 to the whole economy as the ship's powder magazine to the ship; and 

 with every breath that we breathe and every meal we eat we are putting 

 one or more of them in peril". It is not quite so bad as that. We know 

 from experience that sudden explosions in the economy are not to be 

 feared. We can rely upon the mechanism keeping intact under ordinary 

 conditions for a certain period of time with somewhat the same con- 

 fidence that we have that the earth will stick to its orbit and not take 

 a tangential dive into outer space. A timid person might work up a 

 scare with reference to that operation of nature also if he once gave 

 himself up to the possibilities of things going wrong. 



But while experience teaches us that the machinery is not likely to 

 go to pieces all at once we know that it does break down in places very 

 frequently. In later life particularly these failures in adjustment or 

 adaptation thrust themselves disagreeably upon our attention. Slight 

 deviations from the normal that at first seem to be of little importance 

 grow into serious pathological defects which must be treated by the 

 methods of medicine or surgery. The body must grow old of 

 course. We accept senescence as a law of our being and in the long 

 run senescence may be regarded as a gradually developing loss in the 

 power of adaptation of the tissues to their internal environment, an 

 increasing imperfection in the processes of nutrition; but by unhygienic 

 living, by deliberate or ignorant disregard of the rules of health, we can 

 bring about a premature disruption of one or more of the delicate adjust- 

 ments of the body. A perfect system of preventive medicine would 

 detect these deviations from the normal at the very beginning and would 

 correct them by the application of hygienic measures. Sir James 

 MacKenzie in a recent address before the Pathological Club of Edinburgh 

 laid great emphasis upon this idea. Ordinarily when a patient gets into 

 the hands of the consultant or the hospital physician things have gone 

 too far for simple hygienic treatment, recource must be had to surgery 

 or drugs. MacKenzie thinks that it is the special duty and opportunity 

 of the practicing physician and particularly the family physician to 

 investigate these troubles in their incipiency at a time when mild hygienic 

 treatment may restore the normal status. Every one will admit that 



