REMOVAL OF INHERITED TENDENCIES. 439 



a molecular contest of refined organic principles, not visible or audible 

 in its details, but in general scope and outcome as manifest and benefi- 

 cent in its operation as its more familiar congener. 



Though the conservative influence of reversion is quite apparent in 

 variations of a normal kind, it is far more so in those that are morbid 

 or abnormal. Here the struggle between the variation and the ten- 

 dency to the maintenance of durable types is usually so sudden, vio- 

 lent, and quickly decisive, that it is vividly realized. Upon the ten- 

 dency of deranged actions to revert into the old channels of health 

 does the therapeutist ground all hopes of his ability to assist in the 

 process. When that is manifestly impotent, no means he can bring to 

 bear will arrest the speedy termination of life. Cullen attributed the 

 tendency in disease to reversion or recovery for they are identical 

 to a vis medicatrix natures. The conception is little more than a 

 barren ideality, and does not accord with the fundamental truth that 

 of causes we can know nothing only of the relations of phenomena 

 to each other. The vis medicatrix natural has not been shown to 

 have any antecedent ; it is simply a name for a supposed entity, appar- 

 ently latent until disease appears. According to the views here ad- 

 duced, it is resolvable into the general principle manifest in all kinds 

 of organic life : the strong tendency to the maintenance of characters 

 which a great lapse of time has proved are the most fit. If this gen- 

 eralization be truly grounded, it adds another to some more notable 

 in which modes of action once considered as produced by independent 

 forces were really transmutations of one. 



The frequency with which the principle of reversion gains the 

 mastery in attacks of acute disease is one of the most striking phases 

 of vital action. Form and function are seen to revert to their old 

 types and channels of action as if they had never nearly perished. 

 The struggle against abnormal variations is violent, continuous, but 

 not prolonged. Either the abnormity or reversion quickly gains the 

 mastery ; in the former case the end is dissolution, in the latter health. 

 In some instances the morbid variation is slow, insidious, or mild in 

 nature ; the struggle is then less conspicuous, ' more prolonged, but 

 never suspended. When the abnormal variation gains the mastery, it 

 does not survive or establish its fitness by indefinite perpetuation, and 

 so acquire the prepotency of reversion. Untimely death is the signal 

 and sequel of its mastery, and until this or reversion gains supremacy 

 no peace or continued harmony of action is possible. True, blood 

 affected by a morbid variation chronic in its nature often displays 

 sluggish and varying fortunes in its struggle with reversion for mas- 

 tery ; favoring conditions now giving reversion the ascendancy, then 

 unfavorable conditions impart a renewed energy to the unhealthy ten- 

 dency. Yet a marked lineage struggle for survival is rarely very ex- 

 tendedthe compass of a single life's observation not unfrequently 

 witnessing its close. 



