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nervous centres are somehow implicated in its production, 

 but we must for the present be content to accept facts as we 

 find them, and trust that further researches may be able to 

 throw light upon a subject which is now obscure and 

 mysterious. 



Having now considered the hereditary element in insanity, 

 hysteria and its allies, epilepsy, chorea, and alcoholism, I 

 might readily refer also in detail to neuralgia, cephalalgia, 

 migraine, tubercular meningitis, sanguineous apoplexy, loco- 

 motor ataxy, progressive muscular atrophy (Cruveilhier's 

 paralysis), pseudo-hypertrophic muscular paralysis (Du- 

 chenne's paralysis), sclerosis, and other nervous diseases 

 which are alike subject to heredity, but I think I have adduced 

 sufficient evidence to support the principle for which I am 

 contending viz., that whether the nervous system contains 

 the fons et origo of heredity or not, its diseases are markedly 

 hereditary ; furthermore that the pathological differentiation 

 of individuals is manifested to an extraordinary degree by 

 the transmission of nervous diseases, for, given a neuropathic 

 predisposition in the parents, it is found capable of develo- 

 ping a tendency in the offspring not only to itself, but also 

 to hysteria, epilepsy, chorea, insanity, neuralgia, and in fact 

 to ring the changes on every known variety of nervous dis- 

 order or disease. Thus we see in every family, the members 

 of which have inherited a neuropathic predisposition, that it 

 may not only develop into various forms of nervous disease, 

 but that each member has inherited something which the 

 others have not, whilst some may only act as mediums for 

 transmitting the predisposition to a future generation, and 

 at the same time they themselves may show no evidence 

 of its possession. The differentiation of individuals is 

 absolutely necessitated physiologically and psychologically 



