THE CAUSATION OF DISEASE. 23 I 



the average life of the labourer is longer than that of his more 

 fortunate (?) brother, but there are other influences at work to 

 explain this. 



That laborious muscular exercise is not essential to the health 

 of man is proved by studying the families of our aristocracy. 

 There is no proof that lack of laborious exercise has reduced 

 their standard of health. The deterioration in type which 

 often occurs among such families can be explained in other 

 ways. Be it remembered that it is only during a compara- 

 tively recent period in man's history that the muscular system 

 has been subjected to continued, laborious work. Many primi- 

 tive tribes, it is true, are accustomed to long- sustained mus- 

 cular exercise, as in hunting and fighting, but this is very 

 different to continuous heavy labour, which has only fallen 

 to the lot of man within comparatively recent times. Hard 

 work not being the original lot of man, few men take to 

 it naturally, easily, and willingly. Men work through neces- 

 sity, and only by practice does what was once difficult become 

 easy. But in civilized communities there is always a large 

 number of idle vagrants who will not work. Such are rever- 

 sions, for they exhibit that disinclination to muscular work 

 which belonged to their primitive ancestors. What is true 

 of muscular, is also true of intellectual, work. Although many 

 children take naturally to their books, the majority do not : 

 they exhibit the mental tendencies of their remote ancestors, 

 their chief mental delight being derived from a direct contact 

 w^ith nature, such as is obtained by roving about the fields 

 and woods. 



I have taken two instances — viz., that of the publican, and that 

 of the brain-worker leading an inactive mode of life — in order 

 to illustrate my statement that more or less perfect adaptation 

 to many of the pathogenic E's which obtain in a civilized com- 

 munity would take place, if several successive generations were 

 placed under the same E. Many other examples might be 

 given, and the reader has ample opportunity of applying this 

 principle for himself, and of testing its applicability. 



R 2 



