SWAMMERDAM 199 



merdam proved that the irritation of a nerve, com- 

 pletely severed from the brain, may excite a muscle to 

 contract, and further, that a muscle does not increase in 

 volume during contraction, as physiologists had hitherto 

 supposed. He placed the muscle-nerve preparation in 

 a glass tube, drawn out into a fine neck, and filled with 

 water. At the moment of contraction there was no 

 rise of water in the tube, but if anything a fall. He 

 concluded that no material substance passes along the 

 nerve to the muscle, but a mere impulse.-' 



ESTIMATE OF SWAMMERDAM 



We may claim for Swammerdam (l) that he offered 

 the first scientific account of those transformations of 

 animals which had hitherto been so anomalous and per- 

 plexing ; (2) that he gave a powerful impulse to the 

 comparative study of animal structures ; (3) that he 

 did something for the improvement of zoological system ; 

 (4) that he illustrated by a series of examples admirably 

 worked out that method of studying structure and life- 

 history by means of concrete animal types, which still 

 holds its ground as the best form of elementary instruc- 

 tion in biology, and (5) that he made important con- 

 tributions to experimental physiology and embryology. 

 His short and troubled life was assuredly not spent in 

 vain. 



^Glisson's plethysmographio experiment demonstrated in a different way that 

 muscular contraction is not accompanied by an increase of volume, and this 

 was probably the first to be published (Foster's History of Physiology, p. 290). 

 It would be interesting to learn more precisely what were the muscle-experi- 

 ments which Swammerdam demonstrated to Stensen and others somewhere 

 about the years 1666-8. 



