THE INFLUENCES OF NUKTUEE 109 



and not any particular disease, such as some form of 

 insanity. 



It is certain that what was in the parent a weakness 

 or tiredness of the brain (general neurasthenia) may 

 take some other form in the offspring, possibly under 

 provocation a more virulent form, and that it may be 

 shifted from one period of life to another. Dr. F. W. 

 Mott has given interesting cases of what he calls " the 

 law of anticipation " — the tendency that the nervous 

 disturbance sometimes shows to be shunted earlier and 

 earlier in its expression. 



As every one knows there is a rapidly growing con- 

 viction that those who have a marked family predis- 

 position to serious mental instability should not have 

 children. The individual and racial risks are too great. 

 What constitutes " a marked family predisposition to 

 serious mental instability" must be decided by the 

 wise family physician (or by the board of experts who 

 will perhaps grant marriage certificates in the future). 

 But this much is clear, that a common-sense distinction 

 should be drawn between a weak-mindedness and uncon- 

 trolledness which is manifested from birth onwards and 

 is plainly bred in the bone, and a nervous breakdown 

 which occurred in a catastrophe, such as an earthquake, 

 or under a terrible strain, such as that of the trenches. 

 The former will be very heritable, the latter probably 

 not. 



But what we have learned in regard to the importance 

 of nurture leads us further, and we venture to quote 

 from a recent report by a distinguished authority in 



