Page:The Works of William Harvey (part 1 of 2).djvu/478

 reason wherefore, when parts are first produced, and before they have taken upon them the performance of their respective duties, they all look bloodless and pale, in consequence of which they were formerly regarded as spermatic by physicians and anatomists, and in generation it was usual to say that several days were passed in the milk. The liver, lungs, and substance of the heart itself, when they first appear, are extremely white ; and, indeed, the cone of the heart and the walls of the ventricles are still seen to be white, when the auricles, replete with crimson blood, are red, and the coronary vein is purple with its stream. In like manner, the parenchyma of the liver is white, when its veins and their branches are red with blood ; nor does it perform any duty until it is penetrated with blood.

The blood, in a word, so flows around and penetrates the whole body, and imparts heat and life conjoined to all its parts, that the vital principle, having its first and chief seat there, may truly be held as resident in the blood ; in this way, in common parlance, it comes to be all in all, and all in each particular part.

But so little is it true, as Aristotle and the medical writers assert, that the liver and the heart are the authors and compounders of the blood, that the contrary even appears most obviously from the formation of the chick in ovo, viz. : that the blood is much rather the fashioner of the heart and liver ; a fact, which physicians themselves appear unintentionally to confirm, when they speak of the parenchyma of the liver as a kind of effusion of blood, as if it were nothing more than so much blood coagulated there. But the blood must exist before it can either be shed or coagulated; and experience palpably demonstrates that the thing is so, seeing that the blood is already present before there is a vestige either of the body or of any viscus; and that in circumstances where none of the mother's blood can by possibility reach the embryo, an event which is vulgarly held to occur among viviparous animals.

The liver of fishes is always perceived of a white colour, though their veins are of a deep purple or black ; and our fowls, the fatter they become, the smaller and paler grows the liver. Cachectic maidens, and those who labour under chlorosis, are not only pale and blanched in their bodies generally, but in their livers as well, a manifest indication of a want of blood in their system. The liver, therefore, receives both its