THE CAUSATION OF DISEASE. 211 



position. Comparatively few in civilized communities die from 

 sheer want of food, the necessities of life being placed prac- 

 tically within the reach of all. Famine does unfortunately 

 occur from time to time among such,, and when this happens 

 there is probably in some degree a survival of the fittest ; for 

 though the provident, as well as the improvident, are apt to 

 be swept away by a widespread famine, the former would on 

 the whole stand a better chance of surviving. 



Thus, owing to the keen competition for the necessities of 

 life among the lower animals, and among savages, many must 

 die, but in civilized communities few need die from this cause 

 directly. 



I say that among the civilized the actual struggle is rather for 

 wealth than for the actual necessities of life, since food is, to all 

 intents and purposes, placed within the reach of all ; but indi- 

 rectly wealth — and I do not necessarily mean immense wealth 

 — tends to increase the chance of survival. In the country 

 many of the poor live to extreme old age, yet I doubt not that, 

 even here, the moderately wealthy rear a larger number of 

 offspring than the extremely poor, who are unable to bestow that 

 care upon their children which is absolutely necessary to suc- 

 cessful rearing. In towns, however, the difference in mortality 

 between rich and poor children must be very large. This fact 

 is, I believe, well known to insurance companies. It is possible, 

 indeed, that the lower classes are more prolific, be the causes 

 what they may; but, as we shall presently see, the poorer parts 

 of large towns necessarily lead to extinction, if not in the first, 

 at all events in the second or third generation, so that the 

 excessive fruitfulness of the poorer classes doss not lead to a cor- 

 respondingly larger survival. The wealthy congregate around the 

 large squares, or fly to the suburbs, where the conditions of life 

 are more favourable. There can be no doubt whatever that in 

 large towns these latter stand an infinitely better chance of 

 survival than the poor, not only because they are less apt to be 

 carried off by starvation, but because they can command more 

 favourable health-conditions. Now wealth for the most part 

 signifies ability. When the individual has acquired wealth for 

 himself, such acquisition obviously signifies some special apti- 

 tude on his part, and when wealth is inherited the inheritor 



