38 



THE PROTEINS 



THE WHEAT 



0.2 per cent hydrochloric acid. The precipitate weighed 2 grams. The 

 solution of the globulin was dialyzed till free from chlorides and the sepa- 

 rated globulin found to weigh 5 grams. The yield in this extraction was 

 therefore 7 grams, or nearly the same as in the preceding. The composi- 

 tion of preparation 24 is given by the analysis shown in the following table : 



Preparations 23 and 24. 



The globulin contained in the ' ' shorts ' ' from the spring wheat was next 

 extracted by treating 2000 grams with 10 per cent sodium-chloride solution 

 for 3 hours, with frequent stirring, and then squeezing out the extract 

 in a screw-press. After the suspended starch had settled, the extract was 

 decanted and saturated with ammonium sulphate. The precipitate was dis- 

 solved in 10 per cent sodium-chloride brine, and the solution filtered from 

 the insoluble matter. The clear extract was then dialyzed till free from 

 chlorides, and the precipitated globulin found to consist of well- formed 

 spheroids and masses of confluent spheroids. The globulin was strongly 

 colored, since much coloring matter was extracted from the shorts, render- 

 ing the extract a deep red-brown in color. The precipitate was then filtered 

 off, again dissolved in the salt solution and placed in a dialyzer. When free 

 from chlorides, the precipitated globulin was filtered off and found to be still 

 much colored. After partly washing with water it began to dissolve, 1 and 

 was therefore next washed with dilute alcohol and finally with absolute 

 alcohol and with ether. Dried over sulphuric acid, it weighed 2.22 grams, 

 and had the composition shown under the heading ' ' Preparation 25 " in the 

 table on page 39. 



1 This solubility of a globulin is due to the formation of acid compounds which are 

 soluble in water, but insoluble in a dilute saline solution. Cf. Osborne, Journal Amer- 

 ican Chemical Society, 1902, xxiv, p. 39. 



