86 



THE PROTEINS OF THE WHEAT KERNEL. 



Another lot of gluten made from 1000 grams of "straight flour" was 

 treated in exactly the same way as that last described. This gluten was 

 thoroughly extracted with alcohol of 0.90 sp. gr. and the residue dissolved 

 in about 500 cc. of 0.2 per cent potassium-hydroxide water. After standing 

 over night, a very turbid liquid was decanted from the sediment which had 

 formed and treated with very dilute acetic acid added to slightly acid reac- 

 tion. The precipitate produced was washed with water, alcohol, and ether 

 and dissolved again in 0.2 per cent potassium-hydroxide water. The result- 

 ing solution, filtered perfectly clear, was precipitated with 0.2 per cent 

 hydrochloric acid, washed by decantation with water, then with dilute 

 alcohol increased gradually in strength up to absolute alcohol, and finally 

 with ether. When dried over sulphuric acid, a pure white, light mass was 

 obtained. This preparation, 96, was analyzed with the results shown in the 

 table below. 



Again, gluten was prepared in the usual manner and extracted with alcohol 

 until everything soluble in that reagent was removed. The residue was then 

 dissolved in 0.2 per cent potassium-hydroxide water and, in order to carry 

 the operation to an end as rapidly as possible, the solution was at once 

 thrown into a filter. As soon as the filtrate ceased to pass through turbid 

 it was returned to the funnel and the filtration continued in an ice-chest. 

 A considerable portion of the solution was obtained perfectly clear after 20 

 hours. This was then precipitated with o. 2 per cent hydrochloric acid and 

 treated in the usual manner, giving preparation 97. 



Preparations 96 and gj. 



In order to determine whether a loss of nitrogen occurred through pro- 

 longed contact with the alkaline solution, the following experiment was tried, 

 in which the conditions under which preparation 97 was made were repeated 

 and preparation 98 obtained. The rest of the alkaline solution was kept in 

 the ice-box for 3 days longer, during which time the ice melted and the 



