76 THE CONTROL OF LIFE 



important point is, that there is no warrant for believing 

 that these modificational diseases are transmissible. 

 They may reappear generation after generation if the 

 deteriorative peculiarities in environment and nutrition, 

 habits and occupation persist, but they are not truly 

 heritable. It must also be noted that their secondary 

 effects, on general vigour for instance, may last after 

 the deteriorative conditions have been removed. The 

 child of a drunken father may be hereditarily handi- 

 capped in constitution, though he does not inherit any 

 particular modification impressed on the father's body. 

 While it is very important to realise that modifica- 

 tional diseases do not seem to be transmissible, it must 

 be borne in mind that the liability to be modified some- 

 times means an innate constitutional weakness, which 

 is, of course, transmissible. In the same way, it seems 

 sometimes to be true that a slight constitutional defect 

 may not become of serious moment unless it be roused 

 through excess in certain kinds of food. This is prob- 

 ably true of gout. These two considerations should 

 be thought over, for they lessen in actual practice the 

 strictness of the biological contrast between innate and 

 acquired, variational and modificational, peculiarities. 

 (/) A germinal disturbance which results in dishar- 

 mony in the ordinary routine of health may have diverse 

 outcrops in different members of a family, or in successive 

 generations. It may also change in the time of its 

 outcrop. Thus certain nervous disorders seem to 

 appear earlier and earlier in successive generations, as 

 Dr. F. W. Mott has emphasised in his Law of Anticipa- 



