Page:The Works of William Harvey (part 1 of 2).djvu/513

 to the parts ; the augmentative, that which causes increase to the bulk."

This is in accordance with what we find in the egg, where the albumen supplies a kind of purer aliment adapted to the nu- trition of the embryo in its earlier stages, and the yelk affords the material for the growth of the chick and pullet. The thinner albumen, moreover, as we have seen, is used in fashion- ing the first and more noble parts ; the thicker albumen and the yelk, again, are employed in nourishing and making these to grow, and further in forming the less important parts of the body. For," he says, "the sinews, too, are produced in the same way as the bones, and from the same material, viz. : the seminal and nutritive excrementitious matter. But the nails, hair, horns, beak, and spurs of birds, and all other things of the same description, are engendered of the adventitious and nutri- tive aliment, which is obtained both from the mother and from without." And then he gives a reason why man, whilst other animals are endowed by nature with defensive and offensive arms, is born naked and defenceless, which is this : that whilst in the lower animals these parts are formed of remainders or excrements, man is compounded of a purer material, " which contains too small a quantity of inconcoct and earthy matter/'

Thus far have we followed Aristotle on the subject of ' The Order in Generation/ the whole of which seems to be referrible to one principle, viz. : the perfection of nature, which in her works does nothing in vain and has no short- comings, but still does that in the best manner which was best to be done. Hence in gene- ration no part would either precede or follow, did she prefer producing them altogether, viz. : in circumstances where she acts freely and by election ; for sometimes she works under compulsion, as it were, and beside her purpose, as when through deficiency or superabundance of material, or through some de- fect in her instruments, or is hindered of her ends by external injuries. And thus it occasionally happens that the final parts are formed before the instrumental parts, -understanding by final parts, those that use others as instruments.

And as some of the parts are genital, nature making use of them in the generation of other parts, as the means of remov- ing obstacles the presence of which would interfere with the due progress of the work of reproduction, and others exist for