256 A STUDY IN HEREDITY 



APPENDIX G 



It has been asserted that parental drunkenness tends to cause 

 "nervous instability" — whatever that may mean; these vague 

 terms are the bane of science — in the child which, in turn, leads 

 to epilepsy, insanity, and what not. Now if this be true, then 

 alcohol weeds out the unfit much more rapidly than I supposed, 

 and my contention is greatly strengthened. But truth compels me 

 to admit that I have seen no real evidence bearing on this point. 

 Statistics without end I have seen, but the old confusion between 

 post hoc and propter hoc is ever perpetrated. If it be argued that 

 inebriates very frequently have offspring insane or epileptic, I must 

 reply, so have non-inebriates. If it be argued that inebriates have 

 a higher proportion of offspring so afflicted, I must retort that it 

 is precisely from those who have a tendency to insanity or epilepsy 

 that one would expect inebriety, and that though this tendency 

 might not find expression in the parent, and may result only in 

 drunkenness, yet it is to it, and not to the parental inebriety, that 

 the filial epilepsy or insanity is probably due. Moreover, in these 

 statistics no attempt has been made to differentiate between the 

 effect of alcohol on the germ and its effect on the embryo and 

 the foetus. Doubtless this is impossible, for mothers drunken 

 before pregnancy are usually drunken during it, and often the 

 fathers are drunken also. Still, unless it be done, the statistics 

 are inconclusive. No one doubts that alcohol is a poison. Very 

 probably it does in many cases injure the developing brain of the 

 child, with the result that subsequently epilepsy or insanity may 

 supervene. It injures the mother's nervous structures we know, 

 and there is no apparent reason why it should not injure the 

 child's. But this is one thing ; it is not a problem of heredity. 

 The effect on the germ of the alcohol circulating in the parent's 



