EXTRACT II. A. 



ON BIOLOGICAL EVOLUTION, AND ITS INFLUENCE ON 

 PATHOGENESIS, AND TREATMENT. 



IN biological developmental progress we see the natural 

 history aphorism, "the survival of the fittest," supple- 

 mented by the subsidiary, structural, and functional law 

 of the displacement or replacement of the less by the more 

 fit, the less fit gradually, but absolutely, disappearing with 

 the altering environment of the developing organism in 

 its successional progress by natural selection in tissue, 

 organ, and organism, in part and in whole. The truth of 

 these observations is abundantly evident, throughout the 

 whole of animated nature, in the sequence of the steps of 

 advance characterising the whole course of evolutionary 

 progress, from the uni-cellular organism to the last and 

 most highly differentiated and endowed living being- 

 man. Man himself representing, in the various consecu- 

 tive phases of his developmental experience, every stage 

 of organic evolution as it is to be met with in the whole 

 course and stages of the organic life of the globe, both as 

 it has existed and now exists ; with the additional and 

 further evolution of great intellectual endowments and 

 moral attributes, which latter are his peculiar and crowning 

 possessions, although rudiments of intellectual superiority, 

 with a faint glimmering of nascent morality, are not 

 wanting in his higher neighbours in the animal scale. 



It is by the evolution and development of nervine 

 structure and function that every stage of organic advance- 

 ment is achieved ; the first, or uni-cellular, form of 

 organism is animated, vitalised, or energised by a sub- 



