502 Transactions of the Canadian Institute. [Vol. VII. 



extracting starch-free gluten with 70 per cent, alcohol, filtering the 

 solution repeatedly, and afterwards evaporating completely to dryness. 



Average of five estimations 0.83 per cent. ash. 



" two " 0.29 " phosphorus. 



GHadin was prepared by extracting gluten with 70 per cent, alcohol, 

 filtering and diluting with twice its volume of i per cent, sodium 

 chloride solution ; the white precipitate, separating out, was collected, 

 washed with distilled water, till free from chlorine, and dried at 1 10 C. 

 The analyses gave : — 



I. II. III. IV. 



Phosphorus 0.19 0.19 0.18 



Ash 0.205 0.201 



Nitrogen 17.705 17.435 17-64 17-555 



The ash from these was dissolved with hydrochloric acid ; the solu- 

 tion evaporated almost to dryness in a platinum crucible, was diluted 

 with distilled water, and treated with a quantity of dilute hydrochloric 

 acid containing also potassium ferrocyanide. A blue colouration im- 

 mediately indicated the presence of iron ; repeated trials invariably 

 yielded the same result. 



In order to determine whether the iron was organic or inorganic, 

 a solution of gliadin in ammonia-free distilled water was added to a 

 solution of haematoxylin. No darkening whatever occurred, showing 

 that the iron must be organically combined. Inorganic iron salts with 

 haematoxylin give an intense dark blue colour. Pieces of freshl}'-pre- 

 pared gliadin, suspended in haematoxylin, gave no reaction in thirty 

 hours. The iron, like the phosphorus, must be in organic combination. 



Previously to this I had found that on digesting gluten with arti- 

 ficial gastric juice, and repeatedly renewing the fluid, a part remained 

 insoluble even after two months. This residue, after extracting with 

 absolute alcohol and ether, was dissolved in 0.2 per cent, sodium hydrate, 

 and precipitated by 0.2 per cent, hydrochloric acid, the precipitate being 

 insoluble in excess of the acid. Evidently this was a nuclein, and must 

 have come from the gliadin or glutenin of the gluten. 



A gram of gliadin, purified by precipitating, dissolving, repreci- 

 pitating, and extracting with absolute alcohol and ether, was digested 

 with artificial gastric juice at sS'^C. A residue remained which gave all 

 the reactions for nuclein, and undoubted reactions also for organic iron 

 and phosphorus. 



