270 SPECIAL HISTOLOGY. 



in one and the same muscle, is extremely variable ; it con- 

 tinues to dimmish as long as it is in action, whence arise 

 the phenomena of fatigue and loss of power in the muscles 

 (E.Weber). 



In the dead muscle, according to the same observer, the 

 elasticity is less perfect ; that is to say, the dead muscle, when 

 stretched, does not altogether resume its pristine form, and 

 consequently is more readily torn, although such a muscle as 

 the gracilis may still be capable of supporting a weight of 

 eighty pounds without breaking. But at the same time it is 

 also less extensible, more rigid, less flexible, — or its elasticity 

 is greater. The phenomena of fatigue in the muscles are 

 consequently to be distinguished from those induced by death. 

 In the former state, the diminution of elasticity occurs during 

 the influence of the nerves and the contractions of the muscle 

 itself, probably in consequence of changed conditions in the 

 molecular nutrition of the muscle, and is consequently a vital 

 phenomenon ; whilst in the latter case, innervation, nutrition, 

 and contraction have ceased, and the increase of elasticity, 

 which produces what is termed the rigor mortis, is a purely 

 physical phenomenon, and not to be confounded with the 

 increased tension, which, under the influence of life, takes 

 place during the contraction of the muscles, simultaneously 

 with a diminution of the elasticity. 



The tendons are very firm, and but slightly elastic ; and 

 contain, according to Chevreuil, in 100 parts, only 62*03 of 

 water, considerably less therefore than the muscles. They 

 consist principally of a substance affording gelatin, although 

 they are transformed with more difficulty than other parts into 

 that principle. 



[In my opinion the muscles are sometimes in a state of 

 tension, sometimes in their natural form, sometimes even 

 compressed, and to all these three conditions vital contraction 

 may be superadded. If a muscle in a state of extension 

 contract, so as not to assume its natural form, it will still be 

 in a state of tension after the remission of the contraction, and 

 if divided will retract. On the other hand, if a muscle in its 

 natural form contract, it will, after the cessation of the nervous 

 influence, immediately become extended ; as, for instance, the 



