of the Salmon in Fresh Water. 113 



pitate was separated. When redissolved in normal salt solution it gave 

 the reactions of musculin. The filtrate after the separation of the 

 musculin was subjected to fractional heat coagulation. The following 

 results were obtained : 



38 deg. C. - Very slight opalescence. 



40 deg. C. Decided opalescence. 



45 deg. C. Milky fluid (filtered clear). 



47-5 deg. 0. Faint cloud. 



48 deg. C. - Distinct cloud 



53 deg. C. Precipitate (filtered clear). 



55 deg. C. Faint cloud. 



60 deg. C. Decided cloud. 



62 deg. C. Precipitate (filtered clear). 



64 deg. C. Faint cloud. 



68 deg. C. Very slight precipitate. 



Heated to 80 deg. C. No further precipitate. 



The solution thus contained : 



(a) A proteid coagulated at from 38 to 45 deg. C. This would 

 correspond to the fibrin-like modification of myosin the soluble 

 myosin-fibrin described by Fiirth, rapidly formed at ordinary 

 temperatures from the paramyosinogen, the formation having prob- 

 ably taken place during the filtration of the original extract, a process 

 which even under pressure is necessarily tedious. 



(b) A proteid coagulated at 53 deg C. myosinogin. 



(c) A proteid coagulated at 62 deg. C. myoglobidin. 



(d) A proteid coagulated at 68 deg. C. present in very small amount. 

 It is possible that this proteid is an albumin derived from the blood. 

 From the method in which the salmon flesh was obtained, it was 

 impossible to wash all the blood out of the tissues by perfusion. 



2. Fractional coagulation with ammonium sulphate. To the fluid 

 extract a saturated solution of ammonium sulphate was added in the 

 proportion of 2 parts of the fluid extract to 1*5 parts saturated solution 

 of ammonium sulphate. The mixture then contained about 23 per 

 cent, ammonium sulphate. A copious white precipitate formed. This 

 was thrown upon a filter paper and washed with 23 per cent, solution 

 of ammonium sulphate. On being treated with water the most of the 

 precipitate went into solution. The fluid thus obtained gave all the 

 reactions of proteid of the nature of a globulin. Precipitation with 

 heat occurred at about 50 deg. C. The fluid gave a precipitate with 

 nitric acid, the xanthoproteic reaction and the biuret reaction. The 

 proteid answered closely to musculin or the paramysinogein of Halli- 

 burton (5). 



After treatment of the muscle extract by fractional coagulation witli 

 ammonium sulphate, the filtrate was saturated with ammonium sulphate. 

 A copious precipitate formed. This \vas removed, and the filtrate 

 examined and found to be entirely free from proteid. The precipitate 

 was collected, washed with saturated ammonium sulphate solution, and 

 redissolved in normal salt solution. The solution was clear, of a faintly 

 golden yellow colour, neutral in reaction, and gave all the reactions of a 

 proteid solution. 



Fractional heat coagulation was carried out 



(a), When the extract was rapidly prepared and quite fresh 

 55 deg. C. A faint cloud 



60 deg. C. Marked cloud. 



