STRIATED MUSCLE. 75 



treraely soft. This is a phenomenon occasionally observed 

 by surgeons in an amputated limb, especially the thigh ; the 

 muscles which have been cut are seized with tetantiSj con- 

 tract, and pass into form No. 2. Nothing hinders their 

 taking this form completely, as they have no longer any 

 lower insertions, and they withdraw towards the root of the 

 limb, and here form a soft, fluctuating, and globular mass, 

 which has been compared to a collection of liquid. It even 

 appears, and it is true, that the muscle is softer under form 

 No. 2 than under form No. 1. If we attempt to reduce the 

 muscle from the second form, we find that it allows itself to 

 be extended easily, and, after having been drawn out, returns 

 perfectly to the shape from which it was diverted, and is 

 thus, exactly as in form No. 1, slightly and perfectly elastic. 

 Besides being softer, its elasticity is slighter under form 

 No. 2, that is, it is more easily diverted from this form than 

 from form No. 1 : this is shown by two of Weber's experi- 

 ments. 



1. This physiologist constructed, out of muscular fibres, 

 twisting pendulums, and, on setting the needle in motion, 

 observed that the oscillations which occurred are more rapid 

 ,when the muscle is under form No. 1 than under form No. 

 2 ; in other words, in experimenting on form No. 2 a slack- 

 ening was observed, which indicates a less degree of elastic- 

 ity and cohesion, the rapidity of the twirling of the needle 

 being always in proportion to the elastic force of the twisted 

 thread. 



2. By a second experiment Weber ascertained that a weight 

 suspended to a muscle under form No. 2 stretched it more 

 than when it was attached to that of another under form 

 No. 1. We can easily understand that the greater the 

 weight the greater the elongation, and that, by constantly 

 adding to the weight, we at length give the muscle under 

 form No. 2 a length equal to that which it would have under 

 form .No. 1, even equal to its length under this form, if 

 stretched out by the same weight ; and, finally, even to a 

 greater length than if stretched out by the same weight 

 under form No. 1. On arriving at the weight which yields 

 this last result, we notice an apparently paradoxical phenom- 

 enon, which is, that by loading with this weight a muscle 

 under form No. 1, and then making it pass by some excita- 

 tion into form No. 2, we find that, instead of shortening 

 under the influence of the weight, on the contrary it length- 

 ens, which is simply the result of the muscle under form 



