102 THE CAUSATION OF DISEASE. 



under the E which obtained during the exhibition of that 

 particular state than under any other. It does not, of course, 

 necessarily follow that reversion to an ancestral state will in all 

 cases follow on a return to such E — that all domesticated 

 plants and animals, for instance, will necessarily revert to their 

 wild state if exposed to their original E. All I maintain 

 is, that such reversion is far more apt to occur under that 

 form of E than under any other. Darwin was careful to point 

 out that the evidence in favour of the common statement, that 

 reversion to the wild state always takes place under the pre- 

 domestic E, is difficult to obtain. He, nevertheless, writes as 

 follows : "As our varieties certainly do occasionally revert, in 

 some of their characters, to ancestral forms, it seems to me not 

 improbable that, if we could succeed in naturalizing, or were 

 to cultivate, during many generations, the several races, for 

 instance, of the cabbage, in very poor soil (exposing them, that 

 is to say, to an E very like the original ancestral one), they 

 would, to a very large extent, or even wholly, revert to the 

 wild aboriginal stock."* 



I make no doubt that, under the kind of E 1 have denoted, 

 many hereditary weaknesses might be obliterated — nay, even 

 more than this, that a most deteriorated race could again 

 recover its original perfection. Let us take a typical cockney, 

 stunted in body and mind — 5ft. 2in. in height, with his 

 other measurements proportionally dwindled — I make no 

 doubt that if this man, with his cockney wife, were placed 

 under such an E as I have sketched, and their children 

 and grandchildren after them, the physique would rapidly 

 assume its pristine mould. Such thoughts should give us 

 hope. Are there not many particulars wherein we are 

 inferior to our ancestors? Take the single instance of the 

 teeth. It is known that the teeth of civilized peoples are 

 getting worse and worse. What others think of this I know 

 not, but to my mind it is a very serious matter. I suppose 

 primitive man practically never suffered from toothache. How 

 different with us ! If we could reckon up the agony suffered 

 by those now living from toothache, what a terrible total we 



* " Origin of Species," sixth edition, p. II. 



