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 plethysmographic 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 Ilistori/ of Physiology, p. 290). 

 It would be interesting to learn more precisely what were the musclo-expori- 

 nients which Swammerdam demonstrated to Stensen and otheni somewhere 

 about the years 1666-8. 



