by blowing them up with air, after being properly evacuated and cleansed, an invention which developed and stiffened the parts as effectually as an injection of wax, while it did not render them opaque and confused, as that substance is liable to do.
He obtained his degree as Doctor of Physic on the 22d February, 1667, after a public defence of his thesis on Respiration. On this production he again concentrated his attention, and after thoroughly revising and enlarging it, speedily committed it to the press. It was published in the March following, and dedicated to his friend and patron Thevenot. Like all this author's works, it is distinguished for its originality, and most of the statements made, are the result of patient observation and experiment. But many of its views were too much opposed to generally received opinions, to be readily admitted; and the occasional introduction of extraneous matter, laid the work open to objection. Among other attempts made to refute its doctrines, there was one by John Baptist Van Lamsweerde, more remarkable for acrimony than talent, in a publication entitled, "An Expiration of Swammerdam's System of Respiration." But the work contained so many valuable observations and experiments, that it had no difficulty in withstanding these desultory, though spirited attacks, and ultimately took its place among those which have materially contributed to advance our knowledge of animal economy. No fewer than three editions have been printed at Leyden, of the re-
