PRACTICAL CONSIDERATIONS 303 



" anticipation," Prof. F. W. Mott, looks at the problem in another 

 way. He supposes that unsound determinants in the germ-cells 

 may be attracted to one another, " and as it were coalesce or 

 crystallise out," thus causing the disease to appear in a more 

 intense form and at an earlier age. 



In the present state of our knowledge it is impossible to be 

 otherwise than vague in regard to these things. It may be 

 useful, however, to recall Weismann's subtle conception of the 

 struggle of determinants within the germ-plasm, which he sup- 

 poses may account for alleged cases of definite variation in a given 

 direction. Perhaps this " anticipation " is of the nature of a 

 definite variation, though as it happens in a fatal direction — a 

 facilis descensus Averni. 



But the practical importance of the fact of anticipation is 

 obvious. It is one of Nature's many devices to eliminate unfit- 

 ness, to sift out the unsound members of the stock. The diseased 

 condition is pushed further and further back, even to birth, or 

 even before it ! 



§ 12. Practical Considerations 



A medical authority (quoted by F. Martius, 1905) goes the 

 length of saying, " For the practitioner the concept of heredity 

 is quite useless, and he should not deal with it at all. What 

 is wrought out during the life of the individual can be dealt with. 

 What is due to the parents is unalterable.^ 



This is an extreme expression of the practical pessimism which 

 many feel. We cannot choose our parents ; we cannot refuse 

 our legacy. 



But this extreme pessimism is unwarranted. The fact is that, 

 if " the inheritance of disease " really occurred to the extent and 

 in the manner many medical writers assume with so much convic- 

 tion, the human race would have been extinct long ago, or in any 

 case we could not now have the broad and strong stream of 



