which stands the maintenance of the bodily health, not to be understood in all its elements, in all its dependencies, without the most perfect knowledge of every organ and function that constitute the complex Organisms of which Life is at once both Cause and Effect, in connection with the cosmical agencies amid which they exist.

SECTION IX.

THE LACTEAL VESSELS. ASELLI.

PECQUET.

THERE is an important element in the vascular system, though it has no immediate part in the circulation of the blood, that must not be passed without notice by us all the more as Harvey's failure to recognize its significance and real importance has afforded his detractors an opportunity to call his character for candour and liberality into question. This is the system of lacteal vessels, with the discovery of which Aselli, as having been the first to describe them particularly, is fairly enough credited, although its trunk at all events had been already spoken of by Bartholomæus Eustachius, and others.

Aselli, Professor in the University of Bologna, was born at Cremona in 1580, and died in 1626, when no more than forty-six years of age. We learn from himself that he discovered the lacteal veins accidentally,

whilst dissecting the body of a dog to show some friends the course of the recurrent nerve in 1622, although the important fact was not made publicly known until five years afterwards.' When Aselli saw the lacteals first, he took them for nerves; and it was only on puncturing one of them, and seeing the milky fluid which escaped, that he discovered them to be vessels. Aselli, however, failed to follow them through the mesenteric glands-called pancreas Aselli-to their true terminations, in a common duct. Prepossessed by the idea of the liver as the organ of the hæmapoesis, he represents them erroneously in the wood-cuts with which his work is illustrated, as ending on the concave aspect of the great abdominal viscus; the vessels depicted being probably lymphatics running from the liver, not lacteals proceeding

to it.

There could be no question about the existence of the new order of vessels on the intestines and mesentery of the dog and other inferior animals; but were

1 In his work entitled De Lactibus seu venis lacteis, quarto vasorum mesaraicorum genere novo invento, Dissertatio, cum figuris. Mediolani, 1627, 4to. The work, published posthumously, besides the figures printed in colours, is illustrated by a fine engraved portrait of the author. His discovery was very speedily generally known, however, this being greatly due to the liberality of Claude Nicolas de Peiresc, one of the better samples of the great French seigneurs of the old regime. Interested in science and delighting in the converse of learned men, Peiresc appears to have entertained the natural philosopher Gassendi in his castle. Informed by Gassendi of the publication of Aselli's work, Peiresc forthwith ordered a number of copies, which he presented in quarters where he believed the new truth announced would receive the attention it deserved.

they also elements in the anatomy of man? Aselli had doubtless looked for them and missed them in the bodies of those who had died of ordinary disease, and he could not well have a living subject for examination, although temptation of the kind used. to be thrown in the way of the old anatomists. We have no intimation, however, that Aselli ever thought of satisfying his scientific curiosity by dissecting a man alive; but he provided an unhappy wretch condemned to death, with a hearty meal a few hours before his execution, and on laying open the abdomen soon after this, the milk white veins were immediately conspicuous upon the bowels and mesentery, a quantity of their contents being farther collected for examination, to the great satisfaction of himself and friends.' Thus far and no further did the discovery of the lacteals go in the hands of Aselli; its completion was reserved for the greater perseverance and higher anatomical skill of Pecquet, the anatomist who followed Aselli in the investigation of the newly discovered system of vessels.

J. Pecquet of Dieppe, an accomplished physician and skilful surgeon, was the first French writer of note who accepted the circulation of the blood without reserve, and made himself honourably known to the world at large as demonstrator of the course and termination of the lacteal vessels and thoracic duct. Aselli, as we have seen, observed the lacteals on the intestines and 1 Gassendi, in Vita Peirescii, p. 283.

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mesentery, and, erroneously, made them end in the liver. Pecquet traced them from the intestines to the mesenteric glands, and from these into a common sac or reservoir which he designated receptaculum chyli, from whence he lost them not again from sight, until, united into a single slender conduit, he saw it terminate at the point of the junction between the jugular and subclavian veins.

Pecquet of Dieppe and Schlegel of Hamburg were in truth the two anatomists who entered most fully into the spirit of the great Harveian discovery. They would prove it for themselves and make trial of the principles it proclaimed. Hence their honourable position, the one-he of Hamburg-as the accomplished expositor and illustrator of Harvey's doctrine of the circulation; the other-he of Dieppe—as discoverer of an important anatomical fact, and the first to apply one of the great principles involved in the Harveian induction. 'Having exposed the artery and accompanying vein in the leg of a dog," says Pecquet, "and punctured the vein, blood of course immediately followed; but tightening the ligature that had been passed round the artery, lo! the stream from the vein ceased forthwith. Slackening the ligature, however, again it burst forth as before. Now if the blood

flows outwards only by the arteries, did we tie the vessel which supplies a limb about to be amputated, the operation might be performed without loss of blood. No sooner imagined than put to the proof. I tie the

crural artery of the dog, avoiding the vein, and amputate the member a little beyond the ligature. Only a few drops of blood escaped from the divided veins; but there was no hemorrhage."

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SECTION X.

ENVY AND DETRACTION FOLLOW THE DISCOVERER.

HARVEY'S views, then, were admitted; the circulation of the blood, through the action of the heart, was acknowledged as an established fact; but envy and detraction followed in the wake of recognition. The circulation of the blood as announced, it was said, was undeniable, but the merit of arriving at it was little the way having been amply prepared for the conclusions finally attained; the fact was of no great moment in itself; and the discovery none of Harvey's making.

Let us look as impartially as we may at each of these statements.

1 Experimenta nova Anatomica. Accedit de motu Sanguinis Dissertatio. Paris, 1641, p. 28 et seq. Dr. Morison, of Paris, a correspondent of Harvey, must have sent him Pecquet's book, the perusal of which, he says, has given him much pleasure. He greatly commends the author "for his assiduity in dissection, for his ingenuity in contriving new experiments, and for the shrewdness he evinces in the remarks he makes upon them." 'With what labour do we attain to the hidden things of truth, when we take the averments of our senses as the guide which God has given us for attaining to a knowledge of his works!" ("Correspondence of Harvey," English version of Works, pp. 595 et seq.)

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