There is an excellent remark in a thoughtful but anonymous paper on Heredity in the _Quarterly Journal of Science_, two years or so ago, which suggests some considerations well worth noting. 'If we look,' says the writer, 'on the intellect as not a single force but a complex of faculties, we shall find little to perplex us in the phenomenon of spontaneity'--that is (in this case), in the appearance of a man of genius in a family not before remarkable in any way. 'Suppose a family who have possessed some of the attributes of greatness, but who, in virtue of a principle equally true in psychology and in mechanics, that "nothing is stronger than its weakest part," has remained in obscurity. Let a man of this family marry a woman whose faculties are the complement of his own. It is possible that a child of such a couple may combine the defects or weaknesses of both parents, and we have then the case of spontaneous imbecility or criminality. But it is also possible that he may combine the excellences of both, and burst upon the world as a spontaneous genius.... Again, we must remember that, even if we consider the intellect as "one and indivisible," it is far from being the only faculty needful for the attainment of excellence, even in the fields of pure science. Combined with it there must be the moral faculties of patience, perseverance, and concentration. The will must be strong enough to overcome all distracting temptations, whether in themselves good or evil. Lastly, there must be constitutional energy and endurance. Failing these, the man will merely leave among his friends the conviction that he might have achieved greatness, if----. We once knew a physician, resident in a small country town, who from time to time startled his associates by some profound and suggestive idea, some brilliant _aperçu_. But a constitutional languor prevented him from ever completing an investigation, or from leaving the world one written line.'