8 4 



THE PROTEINS OE THE WHEAT KERNEL. 



These results show that it is absolutely necessary to filter the alkaline 

 solution of this body perfectly clear before the final precipitation, since other- 

 wise a considerable amount of non-nitrogenous matter will be precipitated 

 with it. Another extraction was made by treating 200 grams of " patent 

 flour " from spring wheat with 10 per cent sodium-chloride solution added 

 in small quantities so as to make a dough. This dough was then washed 

 with 10 per cent sodium-chloride brine until nearly all the starch was re- 

 moved and a gluten obtained similar in all respects to that resulting from 

 treating the flour with water. This gluten was then chopped fine, thoroughly 

 extracted with alcohol of sp. gr. 0.90, and then dissolved at 20 in o. 1 per 

 cent potassium-hydroxide water. The resulting solution was filtered, but, 

 as only a part of the impurities was thus removed, the filtrate was placed in 

 an ice-box in shallow dishes and allowed to deposit a considerable part of 

 the suspended matter. The decanted solution, which was only very slightly 

 turbid, was then precipitated by neutralizing with 0.2 per cent hydro- 

 chloric acid, and the precipitate washed by decantation with water, extracted 

 thoroughly with dilute alcohol, digested with absolute alcohol and then with 

 ether. This preparation, 92, was a snow-white, light, porous mass, easily 

 reduced to a powder. It had the following composition : 



Preparation 92. 



Protein Extracted by Dilute Alkaline Solutions from Gluten after 

 Extracting the Latter with Dilute Alcohol. 



2000 grams of ' ' straight flour ' ' from spring wheat were made into a dough 

 with distilled water, and this was washed with river- water until the gluten 

 was freed as completely as possible from starch. This gluten was then ex- 

 tracted with 75 per cent alcohol as long as anything was removed. The 

 insoluble residue was dissolved in 0.15 per cent potassium-hydroxide water 

 and the resulting solution allowed to stand in a cold room for 48 hours. 

 The solution was thus freed from but a part of the suspended matter. After 

 decanting from the sediment, the solution was neutralized with dilute hydro- 

 chloric acid, the precipitate produced, washed several times by decantation 



