placuit," says the worthy Plempius—"This discovery did not please me at all at first, as I publicly testified both by word of mouth and in my writings; but by and by, when I gave myself up with firmer purpose to refute and expose it, lo! I refute and expose myself, so convincing, not to say merely persuasive, are the arguments of the author: I examine the whole thing anew and with greater care, and having at length made the dissection of a few live dogs, I find that all his statements are most true."[1]
From the first promulgation of the doctrine of the circulation, its progress towards ultimate general acknowledgment can scarcely be said for a moment to have been interrupted. The hostility of the Primeroses and Parisanuses and Riolans never interfered with it in fact; the more candid spirits were rather led to inquire, by the virulence of these weak and inconsistent opponents, who thus hastened the catastrophe of their own discomfiture, and the triumph of the truth. If men's minds were once in danger of being led astray, it was only for an instant, and not so much through the opposition of enemies, as by an erroneous generalization, which a short interval of time sufficed to correct. Cæcilius Folius, a Venetian physician, having met with one of those anomalous instances of pervious foramen ovale in an adult, immediately and without looking farther, jumped to the conclusion that this structure or arrangement was normal, and that the blood passed in all cases by the route he had discovered, from the right to the left side of the heart. Many Italians received with favour the account which Folius immediately published of his discovery;[2] and the natural philosopher, Gassendi, having about the same period had another instance of the kind which Folius encountered, shown to him, concurred with this writer in his views, and by a variety of arguments and objections, strove to damage, and did temporarily damage,
