5IO Transactions of the Canadian Institute. [Vol. VII, 



but separates completely only on heating ; as it cools, however, more or 

 less of the precipitate goes back into solution. A drop of alkali to the 

 acid solution only produces a faint opalescence, which does not increase 

 with additional alkali until the neutral point is reached, when a sudden 

 clouding occurs, and a precipitate settles out on heating. 



A cold alcoholic solution of gliadin filtered clear, clouds slightly 

 in twenty-four hours, depositing a small precipitate which increases in 

 quantity with the length of time under alcohol. It is much more 

 soluble in boiling than in cold alcohol, a saturated solution of the 

 former depositing a heavy precipitate on cooling. Heating to 130° C. 

 in the autoclave renders gliadin insoluble in alcohol. In artificial 

 gastric juice at 38° C. it rapidly dissolves, depositing a small amount of 

 nuclein, and yielding a considerable amount of true peptone, as evi- 

 denced by the deep red colouration with potassic hydrate and cupric 

 sulphate in the filtrate after removal of proteoses by saturation with 

 ammonium sulphate. It is a unique proteid, in that it gives this red 

 biuret reaction before as well as after digestion. In this particular the 

 name " insoluble phytalbumose " applied to it by Martin'^ does not 

 appear appropriate. The proteid is entirely insoluble in absolute 

 alcohol, and is precipitated by strong alcohol from solutions in weak. 

 Addition of salt to a solution of gliadin in 70 per cent, alcohol does not 

 produce precipitation until water is added. Millon's reagent, and nitric 

 acid give the usual proteid reactions. 



Gliadin is distributed throughout the endosperm, especially toward 

 the periphery, where the small proteid granules are much thicker and 

 the starch granules they enclose smaller. It is also contained in bran, 

 and probably in aleuron cells as part of the packing between the aleuron 

 grains, for both bran and shorts yield gliadin to dilute alcohol. 



IV. — Properties of Glutenin. 



Glutenin is almost completely insoluble in salt solutions, water, and 

 alcohol ; readily soluble in dilute acids and alkalis, from which solu- 

 tion the proteid is precipitated unaltered when the solution is rendered 

 neutral to litmus. It has a definite coagulation temperature which lies 

 about 70° C. Gluten dehydrated with absolute alcohol and ether, is very 

 slowly soluble in dilute acids and alkalis, more or less remaining un- 

 dissolved. Experimental evidence seems to show that glutenin exists 

 as such in the wheat grain. Its composition, according to Osborne, is 

 practically identical with that of gliadin, results differing greatly from 



