GLOBULINS. 45 



solution with neutral salts, like 'sodium chlorid. They 

 are coagulated by heating with water. By the action of 

 dilute acids they are converted into acid albumin. A com- 

 mon example is myosin, which is found in muscle. 



97. Prepare myosin from lean meat by chopping 

 about an ounce finely, then stirring it well with cold water 

 to remove the albumin. Filter through muslin, and repeat 

 the treatment with water until it is white or nearly so. 

 Squeeze out most of the water and treat the residue with 

 a 10-per-cent. solution of ammonium chlorid. For thor- 

 ough extraction it should stand several hours, but enough 

 for testing can be obtained by stirring for five minutes. 

 Filter through muslin, then through paper. The filtrate 

 contains the globulin (myosin). 



98. To a beaker full of pure water add a little of the 

 solution. The myosin is precipitated. 



99. Heat some of the globulin solution. It is coagu- 

 lated. 



100. To 5 cubic centimeters of the myosin solution add as 

 much saturated ammonium sulphate solution. A precipitate of 

 the globulin forms. Is it chemically changed? 



101. Saturate 10 cubic centimeters with magnesium sul- 

 phate. The globulin is precipitated, but dissolves again on dilu- 

 tion with water. Has it been changed chemically? 



102. To the solution of myosin add enough hydrochloric 

 acid to make it contain 0.1 per cent. After it has stood a few 

 hours syntonin, an acid albumin, has been formed. If the change 

 is complete it does not coagulate upon heating. If there is a 

 coagulum it is some of the unchanged myosin. In this case filter 

 it out and test the filtrate for the acid albumin by carefully neu- 

 tralizing it with dilute sodium hydrate. The acid albumin which 

 is formed from the globulin by the dilute acid is precipitated. 



103. Try the general tests for albuminous substances (xan- 

 thoproteic, biuret, Millon's). The myosin responds to all. 



