REMOVAL OF INHERITED TENDENCIES. 443 



only made obvious now and then before development by some mild 

 aggravating cause, such as, when toward dyspepsia, by slight sensa- 

 tions of discomfort after hearty meals ; when toward tuberculosis, by 

 frequent signs of catarrh after ordinary weather-changes. 



Not so much by plain evidences to the senses as by mental analysis 

 can the reality of a struggle between a diathesis and reversion to the 

 normal type be apprehended. Yet it is only the vis medicatrix 

 naturae of medical writers carried from the very obvious in acute dis- 

 ease to the less perceptible in chronic, and to the imperceptible in the 

 diathetic. Although the opinion is very generally entertained that 

 those who inherit a diathesis should be careful as to their mode of 

 life, what effect there is on practice is commonly more injurious than 

 beneficial. This arises from the lack of expert supervision, and the 

 sway of some popular traditions as shallow as they are unsound. 

 More frequently does their observance act as aids instead of hindrances 

 to the development of an inherited dyscrasia. Then the observance 

 of the true conditions which favor reversion in an inherited diathesis 

 require no little judgment, self-denial, patience, and intelligence. In 

 acute disease the physician and nurse see that the conditions of re- 

 version are duly observed. Reputation, love, and alarm are all brought 

 to bear for their enforcement. In a diathesis none of these are evoked 

 until the development of all its signs renders the fact apparent that the 

 fatal work has reached its culminating stage. The diathetic subject 

 while in good health is himself indifferent and incredulous as to his 

 danger. For the young to be always as careful of their health as an 

 invalid, in other words, not to live and do as the careless multitude, 

 presupposes unusual self-denial and discretion. Obstacles like these 

 not only thwart the principle of reversion, but contrariwise strengthen 

 and evolve abnormal variations. 



Advantage being carefully taken of reversion in acute disease, less 

 so in chronic, and scarcely at all in diathetic, that the eradication of 

 unfortunate inheritances should have received so little credence is the 

 natural outcome of the prevailing ignorance or neglect of the condi- 

 tions. It is well, however, to bear in mind that this prevailing belief 

 is simply and wholly the result of antecedents as they are and have 

 been, not as they might and should be. 



The instances in which the operation of the law of reversion has 

 had anything like an unimpeded sway are far more commonly casual 

 than designed. Circumstances render a change of environment and 

 habits of life necessary or desirable, and these may happen to include 

 its favoring conditions, or they may not. Those who recover from the 

 tendency to an abnormal inheritance through intelligent design ought 

 to be found, if anywhere, in the ranks of the medical profession, and 

 especially among those of them who have given the science of health 

 no little attention. A work assigned me by the American Medical 

 Association brought some statements under my eye which confirm this 



