1 64 HEREDITY AND EUGENICS 



Here belong the extreme individualists and anarchists. 

 (4) Knowledge of the mores with presence of the 

 social instincts, but with inability to meet the ex- 

 pectations of society through insufficient inhibition 

 or self-control. This insufficiency may be general 

 and permanent, or it may be temporary (periodic). 

 This would include the hyperkinetic, the hysterical 

 and epileptoid offenders. It is thus evident that 

 a tendency to the inheritance of criminality will vary 

 according to its type. 



Another work by the same author (191 9), on 

 heredit}^ in naval officers, contains genealogical and 

 biographical data of many English and American 

 naval officers, including Raleigh, Hardy, and 

 Nelson. Its attempt to treat thalassophilia, or love 

 of the sea, as an inherited trait is not very happy 

 as a means of analysing the inheritance of men who 

 were, in many cases, remarkably diverse in their 

 exceptional qualities. The Mendelian conception is 

 valuable in connection with so many human traits, 

 that it w^ould be unfortunate if any loose and un- 

 justified usage of it, as in the present instance, with- 

 out any adequate understanding of the nature of 

 the differences involved, should have the effect of 

 throwing doubt on the man}^ cases, mental as well 

 as physical, of Mendelian inheritance in man. It 

 is clearly a matter of greater difficulty to prove 

 the Mendelian inheritance of a mental than of a 

 physical trait, and correspondingly increased caution 

 is necessary. 



A very good summar}'' of the general arguments in 

 proof of the inheritance of mental traits is given by 

 Popenoe (191 6). Failure to recognise the fact of 

 mental inheritance comes largely, now, from certain 

 psychologists and educationists whose biological 

 ignorance and lack of understanding of heredity are 

 a matter for commiseration. Many psychologists, 



