Let us take the case of another still greater and more famous man, Rousseau. It cannot reasonably be doubted that, at some moments in his life at all events, and perhaps during a considerable period, Rousseau was definitely insane. We are intimately acquainted with the details of the life and character of his relations and of his ancestry. We not only possess the full account he set forth at the beginning of his _Confessions_, but we know very much more than Rousseau knew. Geneva was paternal--paternal in the most severe sense--in scrutinising every unusual act of its children, and castigating every slightest deviation from the straight path. The whole life of the citizens of old Geneva may be read in Genevan archives, and not a scrap of information concerning the conduct of Rousseau's ancestors and relatives as set down in these archives but has been brought to the light of day. If there is any great man of genius whom the activities of these fanatical eugenists would have rendered impossible, it must surely have been Rousseau. Let us briefly examine his parentage. Rousseau's father was the outcome of a fine stock which for two generations had been losing something of its fine qualities, though without sinking anywhere near insanity, criminality, or pauperism. The Rousseaus still exercised their craft with success; they were on the whole esteemed; Jean-Jacques's father was generally liked, but he was somewhat unstable, romantic, with no strong sense of duty, hot-tempered, easily taking offence. The mother, from a modern standpoint, was an attractive, highly accomplished, and admirable woman. In her neighbours' eyes she was not quite Puritanical enough, high-spirited, independent, adventurous, fond of innocent gaiety, but a devoted wife when, at last, at the age of thirty, she married. More than once before marriage she was formally censured by the ecclesiastical authorities for her little insubordinations, and these may be seen to have a certain significance when we turn to her father; he was a thorough _mauvais sujet_, with an incorrigible love of pleasure, and constantly falling into well-deserved trouble for some escapade with the young women of Geneva. Thus on both sides there was a certain nervous instability, an uncontrollable wayward emotionality. But of actual insanity, of nervous disorder, of any decided abnormality or downright unfitness in either father or mother, not a sign. Isaac Rousseau and Susanne Bernard would have been passed by the most ferocious eugenist. It is again a case in which the chances of convergent heredity have produced a result which in its magnitude, in its heights and in its depths, none could foresee. It is one of the most famous and most accurately known examples of insane genius in history, and we see what amount of support it offers to the ponderous dictum concerning the insane heredity of genius.