MUSCLE-NERVE PHYSIOLOGY. 501 



presence of a ferment (myosin-ferment). The antecedent myosin in liv- 

 ing muscle has received the name of myosinogen, in the same way as the 

 fibrin-forming element in the blood is called fibrinogen. Myosinogen 

 is, however, made up of two globulins, which coagulate at the tempera- 

 tures 47 C. and 56 C. respectively. Myosin may also, as we have before 

 mentioned, p. 482, be obtained from dead muscle by subjecting it, after 

 all the blood, fat, and fibrous tissue, and substances soluble in water have 

 been removed, to a 10 per cent solution of sodium chloride, or 5 per 

 cent solution of magnesium sulphate, or 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. 



A very remarkable fact with regard to the properties of myosin has 

 been demonstrated by Halliburton, namely, that a solution of dead 

 muscle in strong neutral saline solution, possesses very much the same 

 properties as muscle plasma, and that if diluted with twice or three 

 times its bulk of water, myosin will separate out as a clot, which clot can 

 be again dissolved in a strong neutral saline solution, and the solution 

 can be again made to clot on dilution. This process can often be re- 

 peated ; but in the fluid which exudes from the clot there is no proteid 

 present. Myosin when dissolved in neutral saline fluids is converted in- 

 to myosinogen, but reappears on dilution of the fluid. Muscle clot is 

 almost pure myosin; but it appears to be combined with a certain 

 amount of salts, for if it be freed of salts, especially of those of calcium, 

 by prolonged dialysis, it loses its solubility. If a small amount of cal- 

 cium salts be added, however, it regains that property. 



Muscle serum is acid in reaction, and almost colorless. It contains 

 three proteid bodies, viz. (a) A. globulin (myoglobuliri), which can be pre- 

 cipitated by saturation with sodium chloride, or magnesium sulphate, and 

 which can be coagulated at 63 C. (145 F.). (b) Serum-albumin (myo- 

 ftlfaimiri), which coagulates at 73 C. (163 F.), but is not precipitated 

 by saturation with either of those salts. And (c) Myo-dlbumose, which 

 is neither precipitated by heat, nor by saturation with sodium chloride 

 or magnesium sulphate, but may be precipitated by saturation with am- 

 monium sulphate. It is closely connected with, even if it is not itself, 

 myosin ferment. Neither casein nor peptone has been found by Halli- 

 burton in muscle extracts. In extracts of muscles, especially of red 

 muscles, there is a certain amount of Haemoglobin, and also of a pigment 

 special to muscle, called by McMunn Myo-licematin, which has a spectrum 

 quite distinct from haemoglobin, viz., a narrow band just before D, two 

 very narrow between D and E, and two other faint bands, nearly violet, 

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



In addition to muscle ferments, already mentioned, muscle extracts 



