protein began to form itself into something verging toward organic life, and then there became evolved the nascent life of an organized being. How did the division of the sexes originate? Did some of the molecules or their progressive forms, or their aggregates, or masses, under some conditions, tend to the production of the male, and others under certain conditions tend to the development of the female, so that the sexes were formed by a mere habit of arrangement without any special intervention? Here is one of the most serious difficulties which the doctrine of evolution, whether it be the Darwinian or the Spencerian theory, has to encounter. There is a division into male and female: there is a law of procreation by the union of the two sexes. This is a fact about which there can be no dispute. It is one of the most remarkable facts in Nature. It is the means by which species are continued, and the world is peopled with individuals of each species. Is it conceivable that this occurred without any design, that it had no origin in a formative will, that it had, properly speaking, no origin at all, but that it grew out of the tendencies of organized matter to take on such a diversity in varying conditions? And if the latter was all the origin that it had, whence came the tendencies and whence the favoring conditions that helped them on toward the result? It seems to me that the Spencerian theory, so far as it suggests a mode in which the two sexes of animals came to exist, is hardly less fanciful than what Plato has given us in his "Timæus." I have studied them both.