Again, while considering what women have accomplished for the advancement of science by inspiration and collaboration, we must not lose sight of what they have done by suggestion. For, as John Stuart Mill well observes: "It no doubt often happens that a person who has not widely and accurately studied the thoughts of others on a subject has by natural sagacity a happy intuition which he can suggest but cannot prove, which yet, when matured, may be an important addition to knowledge: but, even then, no justice can be done to it until some other person, who does possess the previous acquirements, takes it in hand, tests it, gives it a scientific or practical form, and fits it into its place among the existing truths of philosophy or science. Is it supposed that such felicitous thoughts do not occur to women? They occur by hundreds to every woman of intellect; but they are mostly lost for want of a husband or friend who has the other knowledge which can enable him to estimate them properly and bring them before the world; and, even when they are brought before it, they usually appear as his ideas, not their real author's. Who can tell how many of the original thoughts put forth by male writers belong to a woman by suggestion, to themselves only by verifying and working out? If I may judge by my own case, a very large proportion indeed."[250] Nor should we forget those active and energetic women--and their number is much greater than is ordinarily supposed--whose husbands, although often endowed with genius of the highest order, were indolent by temperament and disorderly and unmethodical by nature. Such men would, in the majority of cases, have run to seed had not their genius been given special force and impulse by their vigorous and methodical helpmates. Sir William Hamilton, the most learned philosopher of the Scottish school, is a striking instance in point; for it was due almost entirely to the stimulation he received from his ever active wife that he was always kept keyed up to his fullest working capacity as a philosopher and became recognized the world over as one of the commanding intellects of his age.