RIGOR MORTIS. 561 



the formation of acid, the chemical processes which take place in rigor 

 of the muscles 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; but this view must be changed 

 on account of the researches of v. FURTH, which have shown that the 

 clot consists of myogen fibrin and myosin fibrin. 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 oxida- 

 tion product, but a product of the cleavage processes. HERMANN l 

 claims that carbon dioxide is produced in the removed muscle, even in 

 the absence of oxygen, when it passes into rigor mortis. In connec- 

 tion with this view we must call attention to FOLIN'S 2 observations 

 that no protein coagulation took place in rigor under special con- 

 ditions. 



As many investigators admit of an increased formation of lactic acid on 

 the appearance of rigor mortis, the question arises, from what con- 

 stituents of the muscle is this acid derived? The most probable explana- 

 tion is that the lactic acid is produced from the glycogen, as certain 

 investigators, such as NASSE and WERTHER, have observed a decrease 

 in the quantity of glycogen in rigor of the muscle. On the other side, 

 BoHM 3 has observed cases in which no consumption of glycogen took 

 place in rigor of the muscle, and he also found that the quantity of 

 lactic acid produced is not proportional to the quantity of glycogen. 

 It is therefore possible that the consumption of glycogen and the forma- 

 tion of lactic acid in the muscles are two processes independent of each 

 other, and, as above stated in regard to the formation of paralactic acid, 

 the lactic acid of the muscle may be considered as a decomposition prod- 

 uct of protein. The origin of the carbon dioxide is also not to be 

 sought for in the decomposition of the gtycogen or dextrose. PFLUGER 

 and STINTZING 4 found that in the muscle a substance occurs which 

 evolves large quantities of carbon dioxide on boiling with water, and it 

 is probably this substance which is decomposed with the formation of 

 carbon dioxide in tetanus as well as in rigor. In this connection we 

 call attention to the fact that phosphocarnic acid yields lactic acid as 

 well as carbon dioxide as cleavage products. 



After the muscles have been rigid for some time they relax again and 



These works contain also the researches of the earlier investigators more or less com- 

 pletely. 



1 Untersuchungen iiber den StofTwechsel der Muskeln, etc., Berlin, 1867. 



2 Amer. Journ. of Physiol., 9. 



1 Nasse, Beitr. z. Physiol. der kontrakt. Substanz, Pfliiger's Arch., 2; Werther, 

 ibid., 46; Bohm, ibid., 23 and 46; Moscati, Hofmeister's Beitrage, 10. 

 4 Pfluger's Arch., 18. 



