96 ANIMAL MI-X'IIAXISM. 



becoming more and more abundant, invade the entire sub- 

 stance of tin- miiM-le. This phase of alteration, or i'atty dege- 

 neration, is followed by an absorption of the substance of the 

 mii>cle, which disappears entirely at the end of a certain 

 time. 



Thus, not only docs the volume of the organ increase or 

 diminish according as the necessities of its habitual function 

 require a greater or less force, but it wholly disappears when 

 its function is entirely suppressed. This effect is observed in 

 paralysis, where all nervous action is destroyed; in certain 

 cases of dislocation, which bring closer together the two inser- 

 tions of a muscle, so as to render its action useless; sometimes 

 even in fracture and anchyloses, which, by an abnormal con- 

 nection, render the two extremities of a muscle immovable, 

 and prevent any contraction of its fibres. 



l>ut what will happen, if the muscle, instead of losing all 

 its function, only experiences a change with respect to the 

 extent of the movements which it can execute ? After certain 

 incomplete anchyloses, or certain dislocations, we see the 

 articulations lose more, or less of their movements; as the 

 muscles which command flexion and extension only need, in 

 sinh cases, a part of the ordinary extent of their contraction. 



If the theory just enunciated be correct, these muscles ought 

 to lose a portion of their length. In order to verify this fact, 

 we have only to make a short exclusion into the domain of 

 pathological anatomy. 



A warm discussion arose, some twenty years ago, as to the 

 transformation which the muscles underwent in those patients 

 who were alllicted with the deformity commonly known by the 

 name of i-luli J'nat. Sometimes the foot is twisted upon the 

 leg, so that the surface which should bo uppermost is next 

 tin- -.-round; sometimes the foot is so forcibly extended that 

 the patient* walks continually on its extremity. In all these 

 - the muscles of the leg have only a very limited play ; 

 they under-... ihi rel'c.iv, either fatty or fibrous transformation. 

 Among tliise miiM-les, these which have no longer any action 

 undergo Patty degeneration, and then disappear ; \\hile those 

 whose action is partly pi. at rved, pn scut only a change as to 

 the proportion ,,]' ,-,.,| iil, n . ;i nd tendon. lu the latter 



