It would have been easy for our illustrious colleague to have woven the whole of this web from materials of his own; but to escape the charge of envy, he has rather chosen to take Aristotle and Fabricius of Aquapendente as his guides, and to appear as contributing but his portion to the general fabric. Of him, whose virtue, candour, and genius are so well known to you all, I shall say no more, lest I should seem to praise to his face one whose singular worth has exalted him beyond the reach of all praise. Of myself I shall only say, that I have done no more than perform the midwife’s office in this business, ushering into the light this product of our colleague’s genius as you see it, consummate and complete, but long delayed, and fearing perchance some envious blast: in other words, I have overlooked the press; and as our author writes a hand which no one without practice can easily read (a thing that is common among our men of letters), I have taken some pains to prevent the printer committing any very grave blunders through this--a point which I observe not to have been sufficiently attended to in the small work of his which lately appeared.[121] Here then, my learned friends, you have the cause of my addressing you at this time, viz. that you may know that our Harvey presents an offering to the benefit of the republic of letters, to your honour, to his own eternal fame. Farewell, and prosper. GEORGE ENT. INTRODUCTION. It will not, I trust, be unwelcome to you, candid reader, if I yield to the wishes, I might even say the entreaties, of many, and in these Exercises on Animal Generation, lay before the student and lover of truth what I have observed on this subject from anatomical dissections, which turns out to be very different from anything that is delivered by authors, whether philosophers or physicians. Physicians, following Galen, teach that from the semen of the male and female mingled in coition the offspring is produced, and resembles one or other, according to the _predominance_ of this one or of that; and farther, that in virtue of the same predominance, it is either male or female. Sometimes they declare the semen masculinum as the _efficient cause_, and the semen femininum as supplying the _matter_; and sometimes, again, they advocate precisely the opposite doctrine. Aristotle, one of Nature’s most diligent inquirers, however affirms the _principles_ of generation to be the male and the female, she contributing the matter, he the form; and that immediately after the sexual act the vital principle and the first particle of the future fœtus, viz. the heart, in animals that have red blood, are formed from the menstrual blood in the uterus.