SKETCH OF THE OD OR SCHWANN. 259 



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 Insti- 

 tute, where we used to work till nightfall by the side of our excel- 

 lent chief, Johann Muller. We took our dinner in the evening, 

 after the English fashion, so that we might enjoy more of the ad- 

 vantage of daylight. Our porter's wife furnished the meat, we the 

 wine and wit. Those were happy days which the present genera- 

 tion might envy us ; happy days when the first good microscopes 

 had been sent out from the shops of Plossi at Vienna, or of Pis- 

 tor and Schick at Berlin, which we paid for by exercising a stu- 

 dent'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." Muller had at that time be- 

 gun 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 physi- 

 ological and microscopical researches for this work. He exam- 

 ined the texture of the voluntary muscles ; pointed out a method 

 of isolating the primary fibers, and demonstrated the origin of 

 the transverse striae 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 dis- 

 proved. He first determined the existence of the proper walls of 

 the capillary vessels, and came very near discovering their endo- 

 thelium. He demonstrated, by physiological experiments with 

 cold water, the muscular contractibility of the arteries. He dis- 

 covered 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 ex- 

 amination and by the re-establishment of the function, the res- 

 torableness 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 contrac- 

 tion. 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 



