544 MUSCLES. 



a protein sui generis. It coagulates at 55-65 C. and is precipitated 

 in the presence of 26-40 per cent ammonium sulphate. Myogen solu- 

 tions are precipitated by acetic acid only in the presence of some salt. 

 It is converted into an albuminate by alkalies, this albuminate being 

 precipitable by ammonium chloride. Myogen passes spontaneously, 

 especially with higher temperatures as well as in the presence of salt, 

 into an insoluble modification, myogen fibrin. A protein, coagulating 

 at 3040 C., soluble myogen fibrin, is produced as a soluble intermediate 

 step. This substance occurs to a considerable extent in native frog- 

 muscle plasma. It does not always occur in the muscle-plasma of warm- 

 blooded animals, and when it does it is present only to a slight extent. 

 It can be separated by precipitating with salt or by diffusion. HALLI- 

 BURTON'S assumption as to the action of a special myosin ferment has 

 not sufficient basis, according to v. FURTH, nor has the often-admitted 

 analogy with the coagulation of the blood. The difference between 

 the musculin and the myogen in their becoming insoluble is that the 

 musculm passes into myosin fibrin without any soluble intermediate steps. 



Myogen may be prepared, according to v. FURTH, by heating, for a, 

 short time, the dialyzed and filtered plasma to 52 C., separating it in 

 this way from the rest of the musculin. The myogen exists in the new 

 filtrate and can be precipitated by ammonium sulphate. The musculin 

 may also be removed by adding 28 per cent ammonium sulphate and then 

 precipitating the myogen from the filtrate by saturating with the salt. 



STEWART and SOLLMANN admit of only two soluble proteins in the 

 muscles. One is the paramyosinogen, which is the same as v. FURTH'S 

 myosin+the soluble myogen fibrin. The other they call myosinogen, 

 which corresponds to v. FURTH'S myogen or to HALLIBURTON'S myosin- 

 ogen-f-myoglobulin. It is a typical globulin which coagulates at 

 50-60 C. The paramyosinogen as well as the myosinogen is readily 

 converted into an insoluble modification, myosin. The myosin of the 

 above investigators is the same as v. FURTH'S myosin fibrin + myogen 

 fibrin, and corresponds, it seems, also to myosin mixed with paramyo- 

 sinogen (HALLIBURTON). STEWART and SOLLMANN differ from HALLI- 

 BURTON in considering that paramyosinogen also coagulates and is 

 converted into .myosin. According to them myosin is also insoluble 

 in a NaCl solution. 



The views of the various investigators differ so essentially and the 

 nomenclature is so complicated (three different things are designated by 

 the name myosin) that it is extremely difficult to give any correct 

 review of the various opinions. 1 Thorough investigations on this subject 

 are very necessary. 



For these reasons the author is not sure whether he has understood and correctly 

 given the work of the different investigators. 



