Page:The Works of William Harvey (part 1 of 2).djvu/552

 formed in the egg? by what agent is either white or yelk turned into blood whilst the liver is not yet in existence ? For in the egg, at all events, he could not say that the blood was transfused from the mother. He says, indeed, " This blood is produced and concocted in the veins rather than in the liver ; but it becomes bone, cartilage, flesh, &c. in the parts themselves, where it undergoes exact concoction and assimila- tion." In this he adds nothing; he neither tells us how or by what means perfect blood is concocted and elaborated in the minute veins both of the albumen and vitellus, the liver, as I have said, not having yet come into existence, not a particle of any part of the body, in fact, having yet been produced by which either concoction or elaboration might be effected. And then, forgetful of what he has previously said, viz. that the hot and hsematous parts are nourished by the vitellus and the cold and anaemic parts by the albumen, he is plainly in contradiction with himself when he admits that the same blood is turned into bone, cartilage, flesh, and all other parts.

More than this, Fabricius has slipped the greatest difficulty of all, the source of not a little doubt and debate to the medical mind, viz. how the liver should be the source and artificer of the blood, seeing that this fluid not only exists in the egg before any viscus is formed, but that all medical writers teach that the parenchymata of the viscera are but effusions of blood? Is the work the author of its workman? If the parenchyma of the liver come from the blood, how can it be the cause of the blood ?

What follows is of the same likelihood : " There is another reason wherefore the albumen should be separated from the yelk, namely, that the foetus may swim in it, and be thus supported, lest tending downwards by its own weight, it should incline to one particular part, and dragging, should break the vessels, in preventing which the viscidity and purity of the albumen contribute effectually. For did the foetus grow amid the yelk, it might readily sink to the bottom, and so cause laceration of that body." Sufficiently jejune ! For what, I entreat, can the purity of the albumen contribute to the support of the embryo ? Or how should the thinner albumen sustain it better than the thicker and more earthy yelk? Or