Also, a man may be barren by reason of the defect of seed, as first, if he cast forth no seed at all, or less in substance than is needful. Or, secondly, if the seed be vicious, or unfit for generation; as on the one side, it happens in bodies that are gross and fat, the matter of it being defective; and on the other side, too much leanness, or continual wasting or consumption of the body, destroys seed; nature turning all the matter and substance thereof into the nutriment of the body. Too frequent copulation is also one great cause of barrenness in men; for it attracteth the seminal moisture from the stones, before it is sufficiently prepared and concocted. So if any one, by daily copulation, do exhaust and draw out all their moisture of the seed, then do the stones draw the moist humours from the superior veins unto themselves; and so, having but a little blood in them, they are forced of necessity to cast it out raw and unconcocted, and thus the stones are violently deprived of the moisture of their veins, and the superior veins, and all the other parts of the body, of their vital spirits; therefore it is no wonder that those who use immoderate copulation are very weak in their bodies, seeing their whole body is deprived of the best and purest blood, and of the spirit, insomuch that many who have been too much addicted to that pleasure, have killed themselves in the very act. Gluttony, drunkenness, and other excesses, do so much hinder men from fruitfulness, that it makes them unfit for generation. But among other causes of barrenness of men, this also is one, and makes them almost of the nature of eunuchs, and that is the incision or the cutting of the veins behind their ears, which in case of distempers is oftentimes done; for, according to the opinions of most physicians and anatomists, the seed flows from the brain by those veins behind the ears, more than any part of the body. From whence it is very probable, that the transmission of the seed is hindered by the cutting of the veins behind the ears, so that it cannot descend to the testicles, or may come thither very crude and raw. SECT. III.--_Signs and Causes of Insufficiency or Barrenness in Women._ Although there are many causes of the barrenness of women, yet the chief and principal are internal, respecting either the privy parts, the womb or menstruous blood. Therefore, Hippocrates saith (speaking as well of easy as difficult conception in women) the first consideration is to be had of their species; for little women are more apt to conceive than great, slender than gross, white and fair than ruddy and high coloured, black than wan, those that have their veins conspicuous, than others; but to be very fleshy is evil, and to have great swelled breasts is good. The next thing to be considered is, the monthly purgations, whether they have been duly every month, whether they flow plentifully, are of a good colour, and whether they have been equal every month.