IX.] PEOPEETIES OF CONTRACTILE TISSUE. 101 



fluid as it filters may be allowed to drop into 



water). 



After a short time decant or draw off with a 



pipette as much fluid as possible, shake up the 



rest and pour about 5 c.c. with the myosin 



suspended in it into each of three test-tubes. 



a. Add drop by drop a strong (e.g. 20 p.c.) salt 

 solution, the' precipitate soon dissolves ; then 

 place it in a water bath at about 50° 0. with a 

 thermometer and heat; at about 57° C. the 

 fluid becomes milky (or a precipitate is 

 formed) owing to the coagulation of the 

 myosin. 



h. Add powdered salt, the precipitate soon 

 dissolves, but when the fluid is saturated 

 with salt is reprecipitated (the precipitate 

 may be in the form of fibrous-looking clumps). 



c. Dissolve the suspended precipitate in salt 

 solution, and test for proteids, e.g. with Xan- 

 thoproteic reaction (cp. Less. iii. § 16 (o)). 



Myosin belongs to the class of globulins ; it will 

 have been seen that it is insoluble in water and 

 in saturated neutral salt solutions, soluble in not 

 too dilute solution of neutral salts, its solution 

 coagulating on boiling (ep. also Less. iii. §§ 11, 

 13, 17, 18). 



15. Syntonin or Acid Albumin. ^ 



Treat a portion of muscle washed as in § 14 

 with ten to twenty times its bulk of HCl "1 p.c. 

 and place in the warm chamber at about 40° C, 



