THE CAUSATION OF DISEASE. 207; 



poisoning, heat, starvation, suffocation, and drowning. If a 

 person be killed in a railway accident, deliberately poisoned, 

 burnt to death, starved, drowned, or suffocated by another, he 

 may be said to have met with a purely accidental death ; but if, 

 on the other hand, through a careless neglect of proper pre- 

 caution, through deliberate purpose or uncontrollable impulse, 

 he break his neck, poison, burn, starve, drown, or suffocate him- 

 self, the cause of death resides in large measure within himself; 

 it is due to an imperfection in his mental self,- rather than to 

 the E — others mentally fitter being naturally selected. 



The non-violent agencies include, among others, all such 

 as are comprised under the term insanitation. Vast numbers 

 of people yearly succumb to these, and in at all events a 

 large number of cases the fault is not their own — is not 

 due to personal carelessness. Thus, many occupations are 

 necessarily fatal, if not to the first, at all events to the second 

 or third generation following them. Deaths thus caused are 

 purely accidental, since the individual is in no way personally 

 responsible for them, and since, moreover, the E is necessarily 

 fatal to all. But it is far otherwise with those — and their 

 number is large — who willingly transgress the laws of health. 

 Here, again, we are dealing with the mentally unfit, who are 

 thus weeded out from the mentally fitter. 



In order to properly understand the influence of natural 

 selection it is necessary to classify E's. As will be pointed out 

 in a future chapter, there is no such thing as a fixed and unalter- 

 able normal E for all. The E can only be considered in relation 

 to the individual. It must be regarded as normal if the indivi- 

 dual is capable of enjoying perfect health within it, but only 

 so far as that individual is concerned ; and it may be regarded 

 as a maUE if the individual cannot live healthily in it. Roughly 

 speaking, we may regard an E as a mal-E when it works an 

 ill effect upon all men, or upon a limited number of men who 

 under a different E can live healthily. 



Now these mal-E's fall into two important classes — (i) 

 The necessarily-fatal -E ; (2) The not-necessarily-fat al-E. By 

 the former I mean an E which is necessarily fatal to each and 

 every member of the human race; by the latter, a mal-E, 

 which produces ill effects in some, but not in all, or, at all 



