MUSCLE. 263 



ous system, and a muscle whose nerve has been severed stiffens 

 more slowly than one whose continuity with the central nervous 

 system has not been destroyed (HERMANN and his pupils v. EISEL- 

 BERG, v. GENDER and BIERFREUND). The nervous system seems 

 also to have a similar influence on the post-mortem acidification of 

 the muscles (GROSS). HERMANN and his pupils consider the rigor 

 mortis as a slowly-proceeding muscular contraction, identical with 

 the ordinary muscular contraction, but it is difficult at this time 

 to determine as to the correctness of this view from a chemical 

 standpoint. 



When the muscle passes into rigor mortis it becomes shorter and 

 thicker, harder and non-transparent, less ductile and acid. The 

 chemical processes which take place in this step are the following : 

 By the coagulation of the plasma a myosin-clot is produced which 

 is the cause of the hardening and of the diminished transparency 

 of the muscle. The appearance of this clot may be hastened by the 

 simultaneous occurrence of lactic acid. Carbon dioxide is also 

 formed, which does not seem to be a direct oxidation product. 

 HERMANN claims that carbon dioxide is produced in the removed 

 muscle, even in the absence of oxygen, when it passes into rigor 

 mortis. The quantity of carbon dioxide and lactic acid produced 

 on the acidification of the muscle is not dependent upon the quick- 

 ness or slowness of the rigor mortis (RANKE, HERMANN). It is not 

 known from what mother-substance these acids are formed. The 

 most probable explanation is that carbon dioxide and lactic acid are 

 produced from glycogen, and the fact that the glycogen in the 

 muscle decreases on stiffening has been asserted positively (NASSE, 

 WERTHER). On the other side, BOHM has shown that cases are 

 found in which the glycogen is not diminished on stiffening, and he 

 has also found that the quantity of lactic acid produced is not pro- 

 portional to the quantity of glycogen. Under these circumstances, 

 as the muscles of starving pigeons, which are free from glycogen, 

 yield, according to DAM A NT, lactic acid after death, it is hardly 

 possible that the two above acids are formed from glycogen. The 

 only remaining explanation is that they originate from the proteids 

 or certain other not well-known constituents of the muscles. 



After the muscles have been stiff for some time they relax 

 again and become softer. This may partly depend on their becom- 



