Page:The Works of William Harvey (part 1 of 2).djvu/506

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406
ON GENERATION.

minute point situated in the centre of his figure of the chick of the fourth day, without stating, however, that it had any pulsa- tion ; and this he did not perceive to be the heart, but rather believed it to be the rudiment of the body. It is certain, there- fore, that Fabricius spoke only from conjecture and precon- ceived opinion of the origin of the liver ; even in the same way as others have done, Aldrovandus and Parisanus among the number, who, lighting upon two points, and perceiving that they did not pulsate simultaneously, straightway held that one was the heart, the other the liver. As if the liver ever pulsated, and these two points were aught but the two pulsating vesicles replying to each other by alternate contractions, in the way and manner we have indicated in our history !

Fabricius, therefore, is either deceived or deceives, when he says, "In the first stage of the production of the chick, the liver, heart, veins, arteries, lungs, and all the organs contained in the cavity of the abdomen, are engendered together ; and in like manner are the carina, in other words, the head with the eyes and entire vertebral column and thorax engendered." For the heart, veins, and arteries are perfectly distinguished some time before the carina ; the carina, again, is seen before the eyes ; the eyes, beak, and sides before the organs contained in the cavity of the abdomen ; the stomach and intestines before the liver or lungs ; and there are still other particulars connected with the order of production of the parts in generation, of which we shall speak by and by.

He is also mistaken when he would have the vegetative por- tion of the vital principle prior in nature and time to the sen- sitive and motive element. For that which is prior in nature is mostly posterior in the order of generation. In point of time, indeed, the vegetative principle is prior ; because without it the sensitive principle cannot exist : an act if the act of an organic body cannot take place without organs; and the sensitive and motive organs are the work of the vegetative principle ; the sensitive soul before the existence of action, is like a triangle within a quadrangle. But nature intended that that which was primary and most noble should also be primary ; Avherefore the vegetative force is by nature posterior in point of order, as subordinate and ministrative to the sensitive and mo- tive faculties.