PHYSIOLOGY OF MOVEMENT. 705 



ferent extractive matters, and then be extracted with 10 per cent, solu- 

 tion of sodium chloride, a large portion of the muscular tissue will be 

 dissolved and will form a viscid fluid. If this fluid be allowed to fall 

 drop by drop into distilled water a flocculent precipitate will be pro- 

 duced ; this precipitate is likewise myosin. As is seen from its method 

 of preparation, myosin is a globulin which is soluble in strong solution 

 of sodium chloride, and which may be precipitated therefrom by dilution 

 with water. Myosin, like other globulins, may be coagulated by heat, 

 although it coagulates at a lower temperature than does serum-albumen, 

 its point of coagulation being- from 55° to 60° C. It is coagulated by 

 alcohol and may be precipitated by an excess of sodium chloride. It is 

 through the action of dilute acids converted into sj'ntonin, or acid albu- 

 men. Myosin is, therefore, the result of coagulation of the proteid of 

 muscle-plasma. 



In addition to myosin, dead muscle contains serum-albumen and 

 various extractive matters, and bodies belonging to the gelatin group. 



In living muscle, on the other hand, myosin is not present, but some 

 substances or substance which in the death of the muscle become con- 

 verted into myosin, just as the fibrin factors present in living blood in 

 the act of coagulation become converted into fibrin. 



The differences already alluded to between living and dead muscle 

 are, without doubt, caused by the appearance of myosin. The process 

 of coagulation of muscle, however, is not directly comparable to that of 

 the coagulation of the blood, for, while in the latter case the alkalinit}' is 

 preserved, in the former case the alkaline reaction of living muscle 

 gives place to a strongly acid reaction. 



Dr. W. D. Halliburton has found that the muscle-plasma of warm- 

 blooded animals is a yellowish, viscid fluid of alkaline reaction, which 

 remains uncoagulated at 0° C, and at the temperature of the air sets 

 into a jelly-like clot, on the subsequent contraction of which muscle-serum 

 of an acid reaction is squeezed out. 



It was found, however, that cold is not the only agent which will 

 prevent the formation of myosin, but that, as in the case of the blood, 

 solutions of certain neutral salts will act similarly. The solutions found 

 most convenient to use were a 10 per cent, solution of sodium chloride, 

 a 5 per cent, solution of magnesium sulphate, or a half-saturated solution 

 of sodium sulphate. The salted muscle-plasma was prepared either by 

 receiving the expressed muscle-juice into excess of one of these solutions, 

 or else by extracting the finely divided pieces of frozen muscle with the 

 solution in question. 



A further resemblance between salted muscle-plasma and salted 

 blood-plasma must be noticed, namely, that on dilution of the mixture 

 of muscle-plasma and salt-solution with water the influence of the latter 



45 



