MUSCLE. 253 



the liquid which drips off, the muscle-plasma, is faintly yellowish in 

 color, alkaline, and spontaneously but slowly coagulates at a little 

 above C., but very quickly at the temperature of the body. In 

 the muscle-plasma of the frog the reaction does not change imme- 

 diately with the coagulation, but the alkaline reaction is gradually 

 changed into an acid one. The liquid which is pressed from tfte 

 clot, the muscle-serum, is always acid. The albuminous body which 

 forms the clot has been called myosin. Besides this, another 

 albuminous body, musculin or paramyosin (HALLIBURTON), is 

 found in the clot. 



Myosin was first discovered by KUHNE, and constitutes the 

 principal mass of the albuminous bodies of the dead muscle, and 

 according to a few investigators it forms the greatest part of the 

 contractile protoplasma. The statements as to the occurrence of 

 myosin in other organs besides the muscles require further proof. 

 The amount of myosin in the muscles of different animals varies, 

 according to DANILEWSKY, between 30-110 p. m. 



Myosin is a globulin whose elementary composition, according 

 to CHITTENDEN and CUMMINS, is, on an average, the following : 

 C 52.82, H 7.11, N 16.17, Sl.27, 022.03 per cent. If the 

 myosin separates as fibres, or if a myosin solution with a minimum 

 quantity of alkali is allowed to evaporate on a microscope-slide to a 

 gelatinous mass, doubly-refracting myosin may be obtained. Myosin 

 has the general properties of the globulins. It is completely pre- 

 cipitated by saturating with NaCl, also by MgSO*, in a solution 

 containing 94$ of the salt with its water of crystallization (HALLI- 

 BURTON). Like fibrinogen it coagulates at -}- 56 C. in a solution 

 containing common salt, but differs from it since under no circum- 

 stances can it be converted into fibrin. The coagulation tempera- 

 ture, according to CHITTENDEN and CUMMINS, not only varies for 

 myosin of different origin, but also for the same myosin in different 

 salt solutions. 



Myosin may be prepared in the following way, as suggested by 

 HALLIBURTON. The muscle is first extracted by a 5$ magnesium 

 sulphate solution. The filtered extract is then treated with mag- 

 nesium sulphate fa substance until 100 cc. of the liquid contains 

 about 50 grms. of the salt. The so-called paramyosin or musculin 

 separates. The filtered liquid is then treated with magnesium 



