THE PRESENT EVOLUTION OF MAN — PHYSICAL 297 



this latter opinion it is impossible not to dissent. No 

 doubt in any epidemic improper treatment, or lack of 

 treatment, even in the case of so mild a disease, may 

 result in a death-rate high as compared to that which 

 occurs in epidemics during which a proper treatment is 

 pursued ; but in view of the very considerable number 

 of deaths caused even among the most resistant races 

 by measles, as well as of the fact that it is so prevalent 

 among such races that no non-resistant person escapes 

 death from it, it is impossible not to believe that this 

 elimination of the unfittest and survival of the fittest has 

 resulted in some evolution in races that have long been 

 familiar with the disease, and that therefore the virulent 

 character of its epidemics among New World races, as 

 compared to the epidemics among the races of the Old 

 World, is due largely to the circumstance that the 

 former races have not been rendered resistant by the 

 survival of the fittest, whereas the latter have. We 

 shall, however, be in a better position to consider this 

 point after a close examination of the following extracts. 



'In considering the reason why some epidemics of 

 measles should have had a malignant type, great stress, 

 in my opinion, is to be laid on mistakes of dieting and ther- 

 apeutic treatment. Without doubt it is here that we have 

 the explanation of the fact, that the disease in past 

 centuries had a much more unfavourable type than in 

 recent times. In forming an opinion, however, on this 

 point, we should bear in mind that many epidemics of 

 measles adduced in evidence from the eighteenth 

 century were, in fact, outbreaks of scarlet fever. But 

 there still remain a considerable number of true 

 measles-epidemics of that period, whose malignant 

 character was due in the last resort, as the chroniclers 

 themselves admit, to the way in which the sick were 

 treated. Even for many of the epidemics of the last 

 ]bhirty or forty years, remarkable for their very consider- 



