one useful end, indispensable to the race, which nature has in view. Such actions fully merit to be called “instinctive.” Indeed the act of generation is ministered to in nature by the most manifold, imperious, general, and inexplicable of all the instincts, and its instinctive character is the most strongly marked of all. It has emphatically for its origin a rigorously determined and precise want, partly painful, partly pleasurable—a mixture of a feeling of privation with a sense of power. Its end is unknown to the agent, or if known is disregarded, and in almost all animals it demands the concurrent and reciprocal action of two diverse organisms. If anyone would deny that it is instinctive in man, I would advise him to study the sad phenomena connected therewith which may be observed in our asylums for the insane. There are other human actions which are sometimes reckoned as instinctive, such as guarding the eye against injury by suddenly closing the eyelids. This action, however, appears to be an acquired art, though the habitual act of winking to keep clean the surface of the eye may be instinctive. Some other actions, however, not generally regarded as instinctive, I should be disposed so to regard. Such are the first _active_ exercises of the senses of seeing, hearing, smelling, tasting, and feeling (the first “looking,” the first “listening,” etc.) which the child performs at the very beginning of its learning to perform them. It would seem, then, as if no one could deny the existence of such a thing as instinct, and yet it has been denied, not only in recent times, but centuries ago. Thus Montaigne sought to explain instinct as but a form of intelligence, while Descartes taught that it was but mechanism. Condillac regarded it as the result of individual experience, and Lemarck considered it to be merely “habit” which had become hereditary. In our own day Darwin has sought to explain it as partly the result of accidental variations of activity, which variations have become naturally selected, and partly the result of intelligent, purposive action which has become habitual and inherited. Let us consider these attempts at explanation seriatim. First as to mechanism: This is an hypothesis no one at present entertains, as everyone now credits animals with sensitivity. Moreover, instincts are not absolutely invariable, but are modifiable according to the degree of “intelligence” which animals possess. They cannot, therefore, be due merely to a mechanism. The attempt to explain “Instinct” by mere “reflex action” is equivalent to an attempt to explain a phenomenon by omitting its most striking characteristic. In “reflex action” we have a sudden response to a stimulus, which response is more or less purposive as regards the time of its occurrence, but has no reference to future events to occur long after the faintest waves of the stimulating action have died out. The very essence of