THE MUSCULAR SYSTEM. 271 



contracted heart, or an isolated muscle excited by galvanism. 

 Consequently, when we speak of the elasticity of muscles, their 

 1 eiision, not only when they are extended, but also in the 

 compressed condition, must be considered; and this appears to 

 me of some physiological importance, as in this way the exten- 

 sion of contracted muscles (heart), and of muscles whose antago- 

 nists arc paralysed, becomes intelligible. With respect to the 

 cadaveric rigidity, the important facts have quite recently come 

 to light, that it may be arrested by the injection of blood 

 (Brown-Sequard) ; and also that it takes place even in the 

 living animal, when the supply of blood to a group of muscles 

 is entirely cut off (Stannius). In the latter case, the irri- 

 tability of the nerves ceases at the same time, and on the 

 restoration of the circulation the normal conditions in both 

 muscles and nerves are also restored. By these facts, all 

 hypotheses respecting the occurrence of the cadaveric rigidity, 

 except that of Weber, are contradicted ; even that of Briicke, 

 which asserts that it is caused by the coagulation of the fibrin 

 existing in the muscular fibre. But at the same time the 

 question also arises, as to what is the proximate cause of the 

 change in the elastic conditions of the muscles, whether it be 

 due to the death or cessation of activity of the nerves, or to 

 the deficient supply of blood to the muscles themselves ? 

 Stannius decides in favour of the former supposition, and is 

 consequently driven to the conclusion, that during life the 

 motor nerves act upon the muscles, by reducing, during the 

 state of repose, their natural amount of elasticity, whilst in the 

 contraction of the muscle the influence of the nerves is 

 momentarily relaxed. Thus, according to Stannius, the rigidity 

 connected with contraction, and vital contraction, would be 

 identical, and nothing more than the condition of the muscle 

 when freed from all nervous influence, and lasting until the 

 nerve again puts the muscle into a state of rest, or its sub- 

 stance is decomposed. I must own that in this view, which 

 moreover had already been proposed by Engel (' Zeitsch. der 

 Wiener/ Aerzte, 1849), J do not at present agree; and in par- 

 ticular would remark, that the circumstance of the contractions 

 which occur during life being much more considerable than 

 those which attend the rigor mortis, appears to be opposed 

 to it.] 



