370 THE MUSCLE-TISSUE. 



ance of rigor mortis ; and that it increases again with the disappear- 

 ance of rigor mortis and beginning putrefaction. 



As regards the significance of his phospho-carnic acid, Siegfried 

 expresses the opinion that it may serve as one of the sources of 

 muscular energy, and he points out that in the working muscle car- 

 boiiic acid must of necessity be formed on hydrolysis of phosphor- 

 carnic acid even though oxygen be absent. In this manner the 

 observation of Hermann would be explained, viz., that a bloodless 

 muscle can still work for a while in the absence of oxygen and give 

 off carbon dioxide. The lactic acid and phosphoric acid which 

 are also known to be set free during muscular activity, Siegfried 

 likewise refers, in part at least, to a hydrolytic decomposition of his 

 phosphor-carnic acid. The question, however, whether the carbo- 

 hydrate and phosphoric acid group only are liberated, he leaves 

 undecided. 



Of the chemical nature of phosphor-carnic acid little is known ; 

 but it is manifestly closely related to the nucleins, and is termed a 

 nucleon. 



Ferments. Of late, Cohnheim has pointed out the remarkable 

 fact that, while the muscle-tissue itself does not contain a ferment 

 which is capable of decomposing the large amounts of glucose which 

 are daily used in the metabolism of the muscles, and while in the 

 pancreas also no such ferment has been demonstrated, extensive 

 glucolysis can be effected by a mixture of fresh pancreatic extract 

 and the muscle-plasma. This suggests a relation between two pos- 

 sible ferments analogous to that existing between trypsin and entero- 

 kinase. 



Of other ferments the muscle-tissue manifestly contains a proteo- 

 lytic ferment, as the tissue readily undergoes extensive auto lysis after 

 removal from the body. Rosell claims to have isolated a trypsinoid 

 ferment of this order with the uranyl-acetate method. In addition 

 to these ferments we find evidence of a ptyalin, a maltase, and a 

 lactic-acid-producing enzyme. A myosin-ferment, which might be 

 responsible for the development of rigor mortis, according to older 

 concepts, does not seem to exist (v. Furth). 



Muscle -Stroma. Of the chemical nature of the so-called muscle- 

 stroma, which remains after the extraction of the soluble albumins 

 with a 5 per cent, solution of ammonium chloride, we know only 

 that the material in question consists of an albuminous substance. 

 It is apparently a native albumin, and, like the soluble muscle- 

 albumins, characterized by the ease with which it is transformed into 

 alkaline album inate on treating with dilute solutions of alkalies. 



According to Danilewski and Holmgren, the structure of the 

 muscle-fibre is in no ways altered by dissolving out the soluble 

 albumins, and it would thus appear that the stroma represents the 

 actual contractile substance of the tissue. Whether or not this is 

 actually the case, however, is as yet unknown. 



The sarcolemma apparently consists of a substance which belongs 

 to the albuminoids, and resembles elastin in its general properties. 



