132 PROTEIDS. 



Coagulation by heat. 



13. Test both solutions with litmus paper and acidify both 

 with dilute acetic acid (commercial acid of 33 pc to 16 

 volumes of water). Heat, it is not necessary to boil, 

 and note the formation of a coagulum, the density of 

 which will vary with the quantity of proteid present. 



K Determination of the temperature of coagulation. 



Use a ^-pint tin mug as a water bath, with wires across its mouth 

 to support the tubes. Fill nearly with water and introduce a thermometer. 



Prepare 3 tubes with 10 CC of the solution in each tinted 

 with litmus : 



(a) The original solution rendered neutral by cautious addition 



of dilute acetic acid. 



(b) Made acid with dilute acetic acid. 



(c) Made faintly alkaline by adding small quantities of carbonate 



of soda (4 p - c -) solution. 



Label each on a piece of paper placed in the mouth 

 of the tube. Raise the temperature of the fluids slowly, 

 and as soon as 40 C. is reached watch carefully for any 

 change in the transparency and note when opalescence 

 occurs, then solidification, and later, at a higher tem- 

 perature, coagulation, i.e., separation of flocculi. Repeat 

 with solution No. 2, and observe that, owing to the 

 presence of the globulin, coagulation commences at 

 a lower temperature. 



Globulins alone. 



Myosin. Fresh meat is cleared of fat and tendons and is finely 

 chopped up and washed in running water until free of colour. It is 



