He longed to withdraw himself into a profound solitude. For this purpose it was necessary he should dispose of the dear and precious cabinet on which he had spent his days, in which he had enshrined his heart, and which had at length become a portion of himself. He must tear himself from it. At this cost he calculated that he would obtain a revenue sufficient for his wants; but the very loss and separation he longed for he could not undergo. Neither in Holland nor in France could buyers be found for the cabinet. Perhaps the wealthy amateurs, who think of nothing but empty _éclat_, did not find in it the glittering species which give us a child's pleasure. The great inventor's collection offered things more serious: the logical order and arrangement of his discoveries; that eloquent and living method which had guided his genius to new achievements. Alas! it perished, scattered abroad. Having been for a long time ill, in 1680, either through weakness, or a disgust for life and men, he shut himself up, and would not go out any more. He bequeathed his manuscripts to his faithful and life-long friend, whom, when dying, he himself styled the "incomparable,"--the Frenchman Thévenot. He died aged forty-three. What really killed him? His own science. The too abrupt revelation wounded and seized upon him. If Pascal saw an imaginary abyss opening before him, what would happen to this Dutch Pascal, who saw the real abyss and the limitless profundity of the unexpected world? It was not a matter of a decreasing scale of abstract greatnesses or of inorganic atoms, but of the successive envelopment and prodigious movements of beings which are the one in the other. For the little we see, each animal is a tiny planet, a small world inhabited by animals still more diminutive, which in their turn are inhabited by others very much smaller. And this, too, without end or rest, except from the powerlessness of our senses and the imperfection of optical science. All men now began to fathom, and incessantly toil in, that infinity which the hand of Swammerdam had opened up to them. From that time Europe laboured therein with diverse aims. Leuwenhoek, precipitating himself upon it, discovered and conquered new worlds. The Italian positivist, Malpighi, showed perhaps the highest boldness. He proved that the insect has a heart--a heart which beats like man's. One has not far to go to endow it also with a soul. Swammerdam, who was living then, was terrified by the fact. He drew back affrighted from the declivity; he wished to keep his footing, and was fain to doubt the existence of the heart.