"We find the blood formed before anything else in the egg and in the product of conception;[174] and almost at the same time the receptacles of the blood, the veins and the pulsating vesicle, become plainly visible. Wherefore, if the leaping point together with the veins and blood, which are all conspicuous as one single organ at the first beginning of the embryo, be accepted as the heart (the parenchyma of which is superadded to the vesicle later in the formation of the embryo), it is manifest that, accepted in this sense, that is, as an organ composed of parenchyma, ventricles, auricles, and blood, the heart in animals is in very truth, as Aristotle would have it, the principal and first generated part of the body; of which part, however, the first and foremost part is the blood, both by nature and in the order of generation."[175] In the following third passage of the same treatise no reconciling interpretations of the master's words are to be found; flat disagreement with Aristotle is declared; and the "Sun of the Microcosm"[176] declines nearly to its simple modern status of a living pump! Harvey says:-- "Nor can I agree with Aristotle himself, who maintained that the heart is the primary generative part and that it is endowed with soul; for, truly, I believe the blood alone to be entitled to these distinctions, since the blood it is which first appears in generation; and that such is the case not only in the egg but also in every fœtus and very early animal embryo, shall at once be made plain.[177] "At the beginning, I say, there appear the red leaping point, the pulsating vesicle, and filaments, derived thence, which contain blood in their interior. And, so far as can be discerned by accurate inspection, the blood is made before the leaping point is formed, and the blood is endowed with vital heat before it is set in motion by pulsation; and, further, as pulsation is begun in and by the blood, so at last it ends in the blood at the final instant of death. Indeed, by numerous experiments done upon the egg and otherwise I have made sure that it is the blood in which the power of returning to life persists, so long as the vital heat has not wholly vanished. And since the pulsating vesicle and the sanguineous filaments derived from it are seen before anything else, it stands to reason in my belief that the blood is prior to its receptacles--the contained, that is, to its container--since the latter is made for the use of the former. Therefore, it is probable that the filaments and the veins and then the vesicle and at length the heart, having organs destined to receive and retain the blood, are made for the sole purpose of transmitting and distributing it, and that the blood is the principal part of the body....