One other grave pathological state remains to be noticed in this connection—insanity. To the relationship of insanity with genius great importance has by some writers been attached. That such a relationship is apt to occur cannot be doubted, but it is far from being either so frequent or so significant as is assumed by some writers, who rake together cases of insane men of genius without considering what proportion they bear to sane men of genius, nor what relation their insanity bears to their genius. The interest felt in this question is so general that we may be fairly certain that the national biographers have rarely failed to record the facts bearing on it, although in some cases these facts are dubious and obscure. They may often have passed over gout without mention, but they have seldom failed to mention insanity whenever they knew of its occurrence. It is, therefore, possible to ascertain the prevalence of insanity among the persons on our list with a fair degree of approximation to the truth as it was known to the eminent man's contemporaries. We thus find that twenty-one were certainly insane at some period during the prime of their lives; that thirteen others were probably, but not certainly, insane at some period earlier than old age, and that in eleven further cases mental decay set in before death took place in old age. It may be added that at least nine committed suicide, and that at least fifteen were to a very high degree eccentric, although there is no clear reason to suppose that they were actually insane. It also appears that in seven cases (two fathers and five mothers) one of the parents became insane, and that in eight cases one or more of the children were insane. So that the insanity of the ascendants and descendants, so far as can be seen, was about equal and by no means excessive. If we include every possible case of insanity which may be inferred from the data supplied by the national biographers, and even if we include that decay of the mental faculties which is naturally liable to occur before death in extreme old age, we find that the ascertainable incidence of insanity among our 902 eminent persons is nearly 5 per cent.
It is certainly a high proportion. I do not know what is the number of cases among persons of the educated classes living to a high average age in which it can be said that insanity has occurred at least once during life. It is doubtless lower, but at the same time it can scarcely be so very much lower that we are entitled to say that there is a special and peculiar connection between genius and insanity. The association of genius with insanity is not, I believe, without significance, but in face of the fact that its occurrence is only demonstrable in 5 per cent, cases, and that it is only in 1 per cent, cases demonstrable in the parents puts out of court any theory as to genius being a form of insanity.
While I cannot compare with any precision the liability of these
