A number of other things remain to be said on this subject, but which I have treated of in the History of Man; however, before I entirely close, I shall make some few observations. The greatest part of animals do not seek for copulation until they are nearly arrived at their full growth; those which have only a particular season in the year have only seminal liquor at that time. A very capable observer of Nature[BK] not only saw this liquor forming in the roe of a Calmar, but even observed the spermatic animals and the roe itself, which have no existence till the month of October, the time when the Calmar spawns on the coast of Portugal, where Mr. Needham made these observations. As soon as the season is over neither seminal liquor nor spermatic animals are longer seen in the milt, which then dries up and becomes imperceptible till the season returns in the succeeding year, when the superfluous nutriment renews the milt, and fills it as before. In the history of the stag we have an opportunity of remarking on the different effects of rutting; the most general is, the increased size of the animal; and in those kinds of animals whose rutting or spawning is only made at great intervals, the extenuation of the body is proportionably great. [BK] Mr. Needham's New Microscopical Discoveries, London, 1745. As women are smaller and weaker than men, of a more delicate temperament, and eat much less, it is natural to imagine that their superfluous organic particles are not so plentiful; from hence their seminal liquor will be weaker, and less in quantity, than that of men. Since, likewise, the seminal liquor of females contains fewer organic particles than that of males, must there not result a greater number of males than females from the mixture of these two liquors? This is really the case, for which it has hitherto been thought impossible to find a reason. About a sixteenth more male children are born than females; and we find that the same cause produces the same effect in all kinds of animals on which we have been able to make this observation. CHAPTER V. EXPOSITION OF THE SYSTEMS IN GENERATION.