I2 7 



epilepsy, alcoholism, hypochondriasis, mania in its every 

 form of ringing the changes upon the whole series of 

 nervous disorders, and perpetuating them unless neutralised 

 by judicious inter-marriages, from generation to generation. 

 No two individuals in any family or generation will be 

 precisely alike any other physically, mentally, morally, or 

 morbidly, but each will, cceteris paribus, have inherited in 

 various degrees a predisposition to neuropathic conditions 

 resulting from molecular morbific instability in the nervous 

 systems of their parents or ancestors. So likewise, to what 

 disastrous results may the union of a pair respectively 

 gouty and scrofulous not lead ? Gout, scrofula, tuberculosis 

 in its protean forms, Bright's disease, heart diseases, 

 haemophilia, cancer, rheumatism, chorea, apoplexy, and 

 the whole host of dyspeptic troubles ! These are but a 

 few of the gross results, yet each individual involved will 

 differ in the quantity and quality of his morbid heritage 

 from every other, and it is thus, and thus, and thus, that 

 I think the so-called metamorphoses in transmission may 

 be satisfactorily accounted for. To sum up : heredity is 

 the law, but the co-existing and interacting law of varia- 

 bility necessitates the differentiation of individuals; and 

 so I regard these transformations in transmission not so 

 much as differences in kind as differences in degree of 

 inheritance affecting certain individuals, and that these 

 degrees may be of the nature of development or neutrali- 

 sation, />., either an increase or decrease of the primary 

 heritage according to the circumstances. As to how these 

 metamorphoses occur, science is as yet silent : we have 

 only to deal with natural phenomena, and to interpret 

 them as best we may. As Ribot says: "We cannot tell 

 why a given mode of psychic activity is transformed in 



