ON THE VIS MED1CATRIX NATURE " 99 



The origin and perpetuation of living forms may be 

 regarded as the dynamic aspect of organic evolution, while 

 the disappearance or cessation of living forms, as they 

 make room for the appearance of others, may be regarded 

 as the adynamic aspect of organic evolution. The two 

 processes are complementary of each other, and must be 

 regarded as equally necessary and essential in the great 

 process of organic evolution as it unfolds itself in ' ' the 

 struggle of life" by the "survival of the fittest." 



The "survival of the fittest" is the result of every 

 organic struggle, whether it takes place in the evolution 

 of the various individual forms of life or in the evolution 

 of the members, organs, and structures of the individual 

 organism within itself, and represents on all such occasions 

 the occurrence of an exhausted or adynamic residuum of 

 degenerate or ' ' used up " organic units. This degenerate 

 or used up residuum, which results from every such organic 

 struggle, becomes a source of danger to the surviving 

 organic units and individual organisms, if retained within 

 or in close proximity to them or their living and function- 

 ally active structures ; it, therefore, becomes a necessity 

 that a machinery should exist by which all such residual 

 material can be removed from the ' * scene of the struggle," 

 to provide an unincumbered "field," if "no favour," for 

 the continuation of this perpetual organic warfare. 



Within the individual organism this machinery exists 

 as, and is actuated by, the vis medicatrix nature, with the 

 intent that the life of that organism may last to its utmost 

 possible limit the operation of that force, if unopposed, 

 being just able to prolong it to that extent, so as to obviate 

 the loss or waste of that organism before it has accom- 

 plished the work of which it is capable. 



This machinery and power, although existing in every 

 vital organism, cannot definitely be separated from its other 

 vital machinery and powers, and subjected to such separate 

 scrutiny and experimental testing as will enable us to make 

 use of it definitely in the treatment of the many "ills to 

 which human" and all "flesh is heir," nevertheless, we 

 are warranted, and called upon, to make use of every 

 fragment of inductive evidence we can obtain on the 

 subject, and every fact which in any way can be said to be 



