EXPERIMENTAL. 59 



solution containing 75 per cent of alcohol. After digesting 2 days with the 

 solvent, the extract was squeezed out in a press and the process repeated 

 three times. Four extracts were thus obtained. These were each concen- 

 trated to small volume, cooled, and the solution decanted from the precipi- 

 tated mass. This was then washed with distilled water. After removing 

 the salts, the substance from extracts i and 2 dissolved to some extent ; 

 that from extract 3 dissolved completely to a turbid solution. By adding 

 sodium chloride the dissolved protein was precipitated. 



The residues remaining after washing with water were treated with abso- 

 lute alcohol and digested with ether. The precipitates obtained from the 

 water washings by adding salt were treated in the same way. From extract 

 i preparation 72 was obtained, weighing 82 grams ; extract 2, preparation 

 73, weighing 57 grams ; from extract 3, after dissolving in water and 

 precipitating with sodium chloride, preparation 74, weighing 11.3 grams; 

 from extract 4 preparation 75, weighing only 1.35 grams, and from the 

 united water washings of 72 and 73 preparation 76, weighing 5.8 grams. 

 The total weight of these preparations was 157.45 grams, equal to 3.94 per 

 cent of the flour taken. Their composition is shown by the analyses given 

 in table 14 on the preceding page. 



EXTRACTION OF GLUTEN WITH DILUTE ALCOHOL. 



Two kilograms of ' ' straight spring- wheat flour ' ' were made into a dough 

 with distilled water of 20, and then washed in a stream of river water of 

 5. After washing until nearly all the starch was removed, the gluten was 

 chopped up fine and digested with alcohol of 0.90 sp. gr. at a tempera- 

 ture of about 20. This extraction was continued with repeatedly re- 

 newed portions of alcohol of the same strength as long as anything was 

 removed. The extracts were united, filtered perfectly clear, and concen- 

 trated to about one-fourth their original volume. The residual solution 

 was then cooled and allowed to stand over night to deposit the separated 

 gliadin. The supernatant solution was poured off and the large amount 

 of protein which had separated was then dehydrated by treatment with 

 absolute alcohol. The decanted mother-liquor from which this protein had 

 separated, and also the strong alcoholic solution which resulted from dehy- 

 drating the precipitated mass, were each precipitated by adding a little 

 sodium-chloride solution. The three products thus obtained were united, 

 digested with fresh quantities of absolute alcohol in order to complete the 

 dehydration, and then extracted with absolute ether. Dried over sulphuric 

 acid, the preparation weighed 82 grams, and formed, therefore, 4. 10 per cent 

 of the flour taken. Dried at 110, this substance had the composition 

 shown under the head " Preparation 77 " in the table on page 60. 



