CHAPTER XVII. 



The Influence of Environment upon Structure (continued) — The Influence of 

 the Post-partem Environment, considered from the Pathological Point of 

 View. 



I have" been at pains to consider somewhat in detail the in- 

 fluence of the post-partem E upon S. Though its influence 

 over structure is insignificant as compared with that of heredity, 

 which is the great determining power, it is nevertheless one 

 which must be seriously taken into account, and it is utterly 

 impossible to take a wide and philosophical view of the 

 causation of disease unless we make a careful study of all 

 those influences which are capable of affecting the body- 

 structure. Pathology is a branch of biology, and must be 

 studied on the lines of general biology. We have seen that 

 disease is nothing more nor less than an improper inter-action 

 of S and E, and our task has hitherto been confined to the 

 elucidation of the question, " What are the causes of S ? " for, in 

 order to state in the most comprehensive terms the causation of 

 disease, we could not be content with specifying the E which 

 takes share in the morbid inter-action — we had also to state 

 all we know as to the causation of the morbidly inter-acting S. 

 I have already observed that, from the pathological point 

 of view, the post-partem E is the most important. Not 

 that the ante-partem E is by any means powerless for evil. 

 The nature of the mother's blood is capable of exerting an 

 enormous effect for good or evil ; and it is highly neces- 

 sary to preserve the mother's nutrition during the months of 

 gestation. Amongst the poorer classes, especially in large 

 towns, the evils of bad E commence before birth ; for the 

 blood of most of their women is both impoverished and im- 

 pure. Wherefore, if we wish to place an individual under a 

 proper E from the earliest period of his existence, we must 



