MUSCLE SERUM 441 



It is highly probable that the formation of muscle clot is due to the presence 

 of a ferment, myosin jerment. The antecedent myosin in living muscle has 

 received the name of myosinogen, in the same way that the fibrin-forming 

 element in the blood is called fibrinogen. Myosinogen is, however, a mixture 

 of two globulins which coagulate at the temperatures 47 C. and 56 C. re- 

 spectively. 



Myosin may also be obtained from dead muscle after all the blood, fat, and 

 fibrous tissue, and substances soluble in water have been removed by subjecting 

 it to a 10 per cent solution of sodium chloride, or a 5 per cent solution of mag- 

 nesium sulphate, or a 10 to 15 per cent solution of ammonium chloride, 

 filtering and allowing the filtrate to drop into a large quantity of water. The 

 myosin separates out as a white flocculent precipitate. The precipitate gives 

 all the globulin reactions. 



Muscle Serum. Muscle serum is acid in reaction, and almost col- 

 orless. It contains three proteid bodies, viz.: A globulin (my o globulin), 

 which can be precipitated by saturation with sodium chloride, or magnesium 

 sulphate, and which can be coagulated at 63 C.; serum albumin (myo- 

 albumin), which coagulates at 73 C., but is not precipitated by saturation 

 with either of those salts ; and myo-albumose, which is neither precipitated by 

 heat nor by saturation with sodium chloride or magnesium sulphate, but 

 may be precipitated by saturation with ammonium sulphate. It is closely 

 connected with, even if it is not itself, myosin ferment. Neither casein nor 

 peptone has been found by Halliburton in muscle extracts. In extracts of 

 muscles, especially of red muscles, there is a certain amount of hemoglobin, 

 and also of a pigment' special to muscle, called by McMunn myo-hematin, 

 which has a spectrum quite distinct from hemoglobin, viz., a narrow band 

 just before D, two very narrow bands between D and E, and two other faint 

 bands, near E b, and between E and F close to F. 



Other Constituents of Muscle. In addition to muscle ferments, 

 already mentioned, muscle extracts contain certain small amounts of pepsin 

 and fibrin ferment and an amylolytic jerment. 



Certain acids are also present, particularly sarco-lactic, as well as traces of 

 acetic and formic. 



Of carbohydrates, glycogen and glucose (or maltose) and inosite are 

 present. Glycogen is present in considerable amount, especially in the 

 muscles of well-nourished young animals. The glycogen is converted to mal- 

 tose in the muscles on standing some hours after death. 



Nitrogenous crystalline bodies, such as creatin, creatinin, xanthin, hypo- 

 xanthin, or carnin, taurin, urea in very small amount, uric acid, and inosinic 

 acid, are all found on extracting dead muscle. 



Salts of potassium and calcium are present in muscle, the chief of which 

 is potassium phosphate. 



