Page:Popular Science Monthly Volume 37.djvu/271

fur-trimmed dressing-gown, living in a poorly lighted room on the second floor of a restaurant which was not even of the second class. He would pass whole days there without going out, with a few rare books around him and numerous glass vessels, retorts, vials, and tubes, simple apparatus which he made himself. Or I go in thought to the dark and fusty halls of the Anatomical Institute, where we used to work till nightfall by the side of our excellent chief, Johann Müller. We took our dinner in the evening, after the English fashion, so that we might enjoy more of the advantage of daylight. Our porter's wife furnished the meat, we the wine and wit. Those were happy days which the present generation might envy us; happy days when the first good microscopes had been sent out from the shops of Plössi at Vienna, or of Pistor and Schick at Berlin, which we paid for by exercising a student's economies; happy days, when it was still possible to make a first-class discovery by scraping an animal' membrane with the nail or cutting it with the scalpel." Müller had at that time begun the publication of his great treatise on physiology, a work of scientific criticism into which he admitted nothing as true that had not been verified by himself or by his assistants under his eyes. Schwann, at his instigation, undertook a number of physiological and microscopical researches for this work. He examined the texture of the voluntary muscles; pointed out a method of isolating the primary fibers, and demonstrated the origin of the transverse striæ of their primitive bundles. He sought for the terminations of the nerves in the muscles, without being able to discover them. He did not accept the ansated termination, which was generally believed in then, but has now been disproved. He first determined the existence of the proper walls of the capillary vessels, and came very near discovering their endothelium. He demonstrated, by physiological experiments with cold water, the muscular contractibility of the arteries. He discovered in the mesentery of the frog and the tail of the tadpole the division of the primitive fiber of the nerves, an observation then without precedent. He first proved, by microscopical examination and by the re-establishment of the function, the restorableness of cut nerves; and he first made use of that faculty in approaching the question of learning whether the sensitive or motor fibers, when stimulated in their middle parts, propagate the irritation toward both the center and periphery at once, or only in one direction. He invented the muscular balance, for measuring the force of the muscle in different states of contraction. He demonstrated that muscular contractility follows the same law as the elasticity of a body which, having the same length as the muscle at its maximum contraction, is stretched out to the length of the muscle at rest. This work on muscular force