352 THE MUSCLE-TISSUE. 



of different substances, and lie has demonstrated that it can be sepa- 

 rated into two fractions, one of which is precipitated by phospho- 

 tungstic acid, while the other remains in solution. In the first 

 fraction he then demonstrated the presence of hexon-bases, while in 

 the second portion mono-amido-acids were found. Thus far, how- 

 ever, only a fraction of the antipeptone has been resolved into sev-. 

 eral components, and we must admit that there is no evidence 

 to show that the remaining portion may not be represented by a 

 single substance. Whether or not this unresolved portion is identical 

 with Siegfried's carnic acid, however, remains to be seen. If so, the 

 remarkable fact would be demonstrated that a peptone may occur in 

 crystalline form. 



As regards the significance of his phosphor-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- 

 bonic 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 w r hile 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 accordingly 

 termed a nudeon. 



Ferments. The ferments which occur in muscle-tissues have 

 received but little consideration. Several varieties apparently exist. 

 It has thus been shown that a pepsin, ptyalin, and maltase are present, 

 and it seems probable that a myosin ferment and a lactic-acid-form- 

 ing enzyme further exist. The two latter, however, have not been 

 isolated. The former are generally regarded as being derived from 

 the digestive glands, and it is supposed that they have found their 

 way into the muscle-tissue more or less accidentally. I have pointed 

 out, however, that no cogent reason exists for regarding the various 

 ferments which are found in the organs, and which in their general 

 behavior resemble the digestive ferments, as identical with these, 

 and I have no doubt that future researches will show that they play 

 an important role in the metabolism of the tissues of the body. To 

 assume that the chymosin which is found in the urine must be iden- 

 tical with the chymosin of the gastric juice, on the basis that its 

 formation in the kidneys, for example, would lack an adequate 

 explanation, seems to me unwarrantable. For we know that a 

 milk-curdling ferment is not peculiar to the mammalian organism, 

 but may occur even in plants. 



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



