422 GENERAL ANATOMY. 



Are the muscles also susceptible of active elongation? Nu- 

 merous facts have been cited in favour of this opinion. Among 

 them, there are some* which prove nothing in its favour; 

 others, reported by Bichat, Autenrieth, Sprengel et Meckel, 

 leave the question still at least undecided. 



It has been also admitted that there is in the muscles & fixed 

 situation, or an action in which they are neither contracted 

 nor elongated. The same may be said of this phenomenon as 

 of the preceding. , 



. 670. The contraction or shortening being the fact best 

 established in the muscular action, it must be examined in de- 

 tail, as well -as its concomitant phenomena. 



The muscle augmenting in thickness at the same time that 

 it is shortened, the simultaneous occurrence of these two phe- 

 nomena, has given rise to a question that has greatly occupied 

 the attention of physiologists, and which is not yet entirely 

 resolved: it is to ascertain if the volume of the muscles changes 

 at the moment of their contraction. 



The experiments of Svvam|nerdam, Glisson, Goddart and 

 Erman, on the diminution of the size of the muscles during 

 their contraction, does not prove decidedly that this dimi- 

 riution takes place. The same obtains with respect to the 

 experiments and the reasonings of Amberger, Prochaska and 

 Mr. Carlisle in favour of augmentation; they leave the ques- 

 tion equally undecided. It is very probable, according to 

 the observations and experiments of Mr. G. Blane, Barzelotti, 

 Mr. Mayo and Messrs. Prevost and Dumas, thai there is no 

 change of volume, and this accords with the opinion of Soem- 

 mering, Sprengel and Meckel; the shortening and swelling of 

 the muscle mutually compensating each other. 



671. The shortening manifests itself by various effects. 

 The swelling is evident to the simplest observation. The* in- 

 duration is sensible to the touch. 



672. The colour of the muscles suffers no change during 

 the contraction. It has been thought that the contrary was 



* V. Barthez, nouv. Um. de la science de Fhomme, tome i. 

 f Barthez, ibid. 



