Some writers have attempted, ridiculously, I think, to connect the sexual impulse with psychological affinity; and Beaunis, almost equally so, to trace it to chemical action, exercised on the protoplasmic cells through certain senses, such as that of smell in the higher animals. Clevenger. Spitzka and others, have regarded it as " protoplasmic hunger," tracing it back, or endeavoring to do so, to those pre-eexual times when protozoa absorbed one another in the sexual act for the perpetua-'on of life. In the same way another writer has endeavored, and with no success, to distinguish between "sexual hunger," or the propagative instinct, as affecting the whole organism, and "sexual appetite," which is a limited and localized desire; assuming that the "sexual need" is but one aspect of the " nutritive need."1 With these sometimes ridiculous, and frequently conflicting, views we have at present no concern, further than to deduce from them a caution against a too crude and hasty conclusion concerning what has occasioned such ingenious differences of opinion.