THE LIFE OF THE AUTHOR.

A most useful occasion was in inciting his spirit at this time in Amsterdam: because the most learned physicians had instituted a college there, to meet together every other week to hold conversations and experiments, especially on medical and anatomical subjects. The observations made there were later edited by Casparus Commelinus, in the years 1666 and 1667, before Swammerdam was created a Doctor of Medicine. He, however, contributed the primary materials for the composition of this little work. He alone delineated with his own hand the figure of the spinal cord, which Blasius published there, in that very college. He wrote, on that subject, to Thevenot that he had discovered thus: 1. the whole spinal cord is merely fibrous. 2. its fibers meet in a certain part of the brain and terminate there. 3. the nerves, likewise fibrous, arise from the fibers of the cord. 4. the whole pia mater the delicate innermost membrane of the brain is extended into hollow sheaths. 5. the marrow, still warm, along with the vertebrae containing it, must be placed most quickly into the cold, to be left there for the space of a day and night; then, with the vertebrae broken open most cautiously, all these things can be seen. This letter was given on April 1, 1666. At the same time, he attempted many things by pushing various liquids into the vessels of living animals. See on Respiration, pp. 103, 107. Also chemical experiments, concerning cold ebullition between salt of urine and Glauber's spirit of salt. Ibid., p. 111. He then wrote that laborious dissertation on Respiration, which he would defend for obtaining the Apollonian laurel in Medical Art; the reading of which teaches that he followed only things thought out by himself, known by experimenting, and supported on all sides by experience, nor did he mix in anything taken from other authors. These things being done, at the end of the year 1666, he returned to Leiden: to be legitimately received into the order of physicians. And, on that occasion, he cultivated a most tight relationship with the most famous van Horne, his former teacher in anatomy. He practiced anatomy with him then, and prepared various things by different methods: for they openly shared their thoughts and discoveries. The professor most liberally supplied everything that was required; the other directed the work, and at the same time drew all the discoveries with his own hand, with the greatest artistry, and sent all the images thus prepared immediately to Matthaeus Sladus, together with the observations. For what was lacking? Materials, instruments, place, and expenses were most abundantly supplied by Van Horne's liberality. Swammerdam's diligence, industry, and most practiced right hand were occupied night and day. First here, in the very house of Van Horne on January 22, 1667, he filled the uterine vessels of a woman with wax material, a most useful beginning, which he later polished further. He was then promoted into the order of physicians, on February 22 of the same year, and defended his diatribe on Respiration in public. He presented it then conceived only in brief propositions, but the following March he published it amplified in the form of a little book at the Gaasbeeks; and dedicated it to the most distinguished Thevenot. There, in the icon of the title, is an elegant figure.