ix THE MUSCLE-ALBUMINS 385 



myosin Kiihne believed to be partially soluble in salt-solutions, and 

 this solution to possess a coagulation-temperature of 56. In the fluid 

 which remained after the myosin had coagulated, the so-called muscle- 

 serum, Kiihne found, in addition to other, not well-defined, albuminous 

 substances, an albumin which coagulated at 47, and which he held 

 to be uncoagulated myosin. Halliburton, on investigating the 

 albumins of mammalian muscle, obtained four different proteids in 

 the muscle-plasma by extracting muscle with 5 per cent magnesium 

 sulphate : 



1. A globulin precipitable by heat at 47 C. (paramyosinogen). 



2. A globulin precipitable by heat at 56 C. (myosinogen). 



3. A globulin precipitable by heat at 63 C. (myoglobulin), occur- 



ring in the serum. 



4. Traces of an albumin (myoalbumin). 



Halliburton now holds with v. Fiirth l that myoglobulin is some myo- 

 sinogen which has escaped coagulation, and that the myoalbumin is 

 derived from adherent blood and lymph, v. Fiirth maintains that 

 mammalian muscle freed from blood and lymph, and extracted with 

 normal salt - solution, only contains ' myosin ' or paramyosinogen, 

 coagulating between 47-50, and 'myogen' or myosinogen, coagulat- 

 ing between 55-60. Stewart and Sollmann 2 say, "there exist in 

 dead muscle two proteids, a true globulin, paramyosinogen, coagulat- 

 ing at about 45-50, and an atypical globulin : myosinogen, coagulating 

 at about 50-65. The latter very readily passes into a modification 

 very similar to, if not identical with, the former." Paramyosinogen 

 seems to be more abundant in dead muscle than myosinogen, or at 

 least more is extracted by such saline solutions as 5 per cent magnesium 

 sulphate. Vincent and Lewis 3 also favour the view that para- 

 myosinogen and myosinogen appear, in fact, to be interchangeable 

 one with the other, or to be possibly both formed from some common 

 precursor present in living muscular tissue which on heating- 

 coagulates at about 47. Vincent and Lewis further applied the 

 graphic method introduced by Brodie and Richardson 4 for registering 

 the contraction of muscles during different temperatures. "Both 

 striped and unstriped mammalian muscle, on being subjected to a 

 gradually rising temperature, show two marked sudden contractions 



1 Halliburton, Handbook of Physiology, 1904, p. 156. 



2 Stewart and Sollmann, Journal of Physiol. 24. 427 (1899). 



3 Swale Vincent and Thomas Lewis, ibid. 26. 445 (1901). 



4 Brodie and Richardson, ibid. 21. 353 (1897), and Phil. Trans. 191. 127 (1899). 

 See also H. M. Veron, Journal of Physiol. 24. 239. (1899). 



2 C 



