THE CAUSATION OF DISEASE. 28 1 



that the agricultural population itself is dying out. He 

 adds : ' ' This refreshing influence on town population has 

 almost reached its limit, and it seems to me that nothing 

 but a grand scheme of State-aided emigration will serve to 

 relieve the plethora of our overgrown cities." Now, if the 

 immigration of country folk has reached its limit, there is no 

 need of thus relieving our congested towns. As we have 

 already seen, family extinction proceeds rapidly in large towns ; 

 and if country and other immigration should cease, the town 

 population would probably sooner or later begin to diminish. 

 A fair standard of health is kept up in the suburbs, and it is 

 from these that the resident population in the more central 

 parts would, in such a case, have to be replenished. That the 

 waste would be repaired with marvellous accuracy and celerity 

 from some source or other there can be no doubt, for fresh 

 openings would be perpetually recurring, and we know how 

 wonderfully the balance between supply and demand is kept 

 up. For my part, I see no reason for believing that the 

 supply from the agricultural population will fail, for we must 

 remember that human beings tend to increase in geometric 

 proportion. But even supposing that it should fail us, are we 

 to believe that there is no other pabulum to feed the organism ? 

 There are countless people scattered over the globe who would 

 soon find themselves in our own great city, for instance, if the 

 necessary openings presented themselves, and a " grand scheme 

 of State-aided emigration"' would merely result in a grand 

 counter-scheme of immigration which would require but little 

 State-aid. 



I cannot, therefore, agree with Dr. Mott when he concludes 

 that the physiological dissolution which inevitably attends 

 civilization must necessarily tend to the decay of nations. 

 Dr. Mott attempts to fortify himself in his conclusion by citing 

 the well-known fact that every civilization has had its growth, 

 arrest, and decay ; but has this decay always, or even ever, 

 gone on, pari passu, or with the growth, arrest, and decay 

 of the physiological unit, viewed in its physical aspect ? 

 Can we trace the decadence of past civilizations to such 

 physiological dissolution? Kather shall we find its origin 

 in an intricate web of causes — political, social, economic, 



