THE MUSCULAR SYSTEM. 285 



obvious j but in pathology also, it may be employed, in expla- 

 nation of the retraction of divided muscles, and the shortening 

 which takes place in muscles whose antagonists are paralysed. 

 The former, as correctly pointed out by E. Weber, depends 

 upon the clastic force, and takes place, as far as I know, only 

 in extended, tense muscles, but not in those which are in a 

 state of contraction, which, on the contrary, when cut across, 

 immediately become lengthened, as may be readily observed 

 in the Frog. It is quite true, that contractions also take place 

 in divided muscles, in consequence of nervous influence; but 

 these are never more than local, and cease without the pro- 

 duction of any important effect on the form of the wound in 

 the muscle. 



The shortening which occurs in the antagonists of paralysed 

 muscles, is not referable either to the elastic force of the 

 non-paralysed muscles, which is much too slight to influ- 

 ence the position of a limb, or to their persistent " tone," 

 but depends simply upon the voluntary innervation of the 

 muscles, which are still in an active condition, and which, no 

 longer meeting with any opposition from their antagonists, 

 draw the limb in their own direction. The persistence of the 

 oblique position which now ensues, may be readily explained 

 without our necessarily assuming the existence of a permanent 

 contraction, when it is considered that muscles, the antago- 

 nists of which are paralysed, never again become elastically 

 tense. In lead-palsy, for instance, when the first contraction 

 of the flexors, consequent upon the paralysis of the extensors, 

 ceases, the former, even under the most favorable circum- 

 stances, become extended only so far as to assume their 

 natural form, a condition from which necessarily results the 

 semiflexed position of the part affected. In accordance with 

 this view, I regard the permanent condition of the unaffected 

 side of the face, in one-sided paralysis of the facial nerve, and 

 that of the upper eyelids in blepharoptosis, as produced, not 

 by a persistent contraction, but as indicative of a state of per- 

 fect rest in the muscles, except when voluntary movements 

 take place. The falling of the upper eyelid is explained by 

 the paralysis of the levator, and the inability of the orbicularis, 

 by its extension after a previous closure, to raise the eyelid 

 beyond a certain point. In the same way the distortion of 



