26 



parents derived from two tainted ancestral stocks are more likely to suffer 

 with an intense form of the disease ; it shows also why more of the offspring 

 are liable to be affected, (and it shows why a certain proportion of the off- 

 spring may escape entirely; but according to the hypothesis thus advanced 

 it does not explain why only relatively few of the offspring are tainted as 

 compared with the numbers born, even though there be convergent neuro- 

 pathic inheritance, that is, the germinal determinants of both parents may 

 be largely tainted and yet fewer offspring are affected by the disease than 

 would be expected. tfln neuroses and psychoses it is not a disease that is 

 transmitted but a predisposition or tendency^ and. some other factor than 

 \ the inborn is required to produce the disease./^ If we ask ourselves the ques- 

 tion : How could Nature best purify an urisouno! stock? the obvious answer 

 would be to cause coalescence or crystallization out of the unsound germinal 

 determinants into a few of the offspring, leaving the germ-plasm of the 

 others free." This would not only purify the stock by segregation but by 

 concentration in one or two offspring ; it would lead to intensification and 

 anticipation of the disease. The .diseased offspring would be unfit for the 

 struggle for existence and propagation. In putting forward this coalescence 

 theory of similar diseased germinal determinants, I may mention in support 

 of it a statement made by Galton in his great work on Natural Inheri- 

 tance. In the process of transmission by inheritance elements derived 

 from the same ancestors are apt to appear in large groups, just as if they 

 had clung together in the pre-embryonic stage, as perhaps they did. & 



Statistical Data Relating to Inheritance and Insanity, especially in Relation 



to Anticipation. 



Six months ago data referring to 508 pairs of parent and offspring had 

 been collected from the records of 464 insane parents whose 500 insane 

 offspring have been also resident in the London County Asylums, and in 

 these the age of the first attack has been ascertained. 



Direct Heredity. 



The following table is compiled from 217 pairs of father and offspring 

 and 291 pairs of mother and offspring. The figures denote the percentage 

 of cases whose first attack occurred within the given age periods. 



