76 MEMOIES OP THE NATIONAL ACADEMY OF SCIENCES. 



preexists in the grain; but tlie investigation on these points isliot altogether condusive and needs 

 to be contimied. 



Assuming that Kreusler's analyses are correct, there can be little doubt that his oat legumin 

 as finally analyzed was diflerent from the proteid at first existing in the potash extract and was 

 essentially altered in composition as well as in solubility during the processes of preparation and 

 " purification." 



VII. — Proteid extracted by Hot Sodium Chloride Solution. 



(Preparation 20.) 



Freshly ground oats were treated with distilled water heated to 65° C. and then sufficient 

 sodium chloride was added to make a 10 per cent solution. When the addition of salt was begun 

 the liquid had a temperature of 60° C. ; when finished the temperatm-e was 45°. The mixture 

 was digested for about an hour at 45° and a portion of the extract was filtered. The filtrate 

 became turbid immediately on cooling. Wheu gently warmed the tiu-bidity completely disappeared. 

 The perfectly clear solution ou further heating coagulated as follows: At 57° C. a very slight tur- 

 bidity was seen that increased but little up to 78°, whence it rapidly augmented with formation 

 of flocks at 85°. 



The remainder of the extract, together with the crushed oats, was heated up to 75° and 

 filtered as rapidly as possible. A perfectly clear filtrate was obtained which became turbid on 

 cooling. The vessel containing the hot extract was placed in a large water bath at 75° and cooled 

 very slowly. A dense deposit formed which closely adhered to the bottom of the dish and under 

 the microscope was seen to consist entirely of minute spheroids about 0.01 mm. in diameter. 



The residual oats, extracted twice again, yielded little more to the hot salt solution. The pro- 

 portion of proteid thus obtained was apparently little, if any, greater than that dissolved by 

 sodium chloride solution at 15° to 20°. 



The deposit of spheroids was almost wholly freed from the mother liquor by simple decantation 

 and was treated with cold 10 per cent sodium chloride solution, in which it dissolved veiy slowly. 

 On warming to about 40° the substance melted to a soft, plastic mass, which became softer as the 

 temperature rose and could be drawn out into glistening threads. At 65° the substance became 

 so fluid that the mass broke up and rapidly dissolved to a clear solution. 



Wheu a portion of this solution was heated to 78° a slight turbidity developed that increased 

 v ery little up to 98°, at which point a few flocks separated. These were filtered out, and the 

 filtrate gave on boiling a considerable coagulum. The filtrate from this coagulum yielded another 

 precipitate on boiling again, and the same result followed these operations to the fourth time. 

 The final filtrate gave with hydrochloric acid a copious precipitate. 



This substance was now prepared in greater quantity in the following manner: Five pounds 

 of ground oats were treated with twelve liters of 10 per cent sodium chloride solution, strained 

 through a hair sieve to remove the husks and then heated to 60° in a water bath of 70° and main- 

 tained at that temi^erature for an hour. The extract was then filtered as rapidly as iiossible. 

 The extract, after decanting fi'om a deposit which separated out ou cooling, was saturated with 

 pure ammonium sulphate, and the precipitate thus formed was filtered oft' and added to the de- 

 posit formed on cooling. The substance thus obtained was then treated with three liters of 10 

 per cent sodium chloride solution heated to 65° in a water bath of 70° and filtered as rapidly as 

 possible on a funnel surrounded by hot water. The clear filtrate, which became turbid at once 

 on cooling, was received in a vessel set in a large water bath heated to 70°, and the whole was 

 allowed to cool very slowly. When cold the liquid was decanted from the dense deposit that ad- 

 hered to the bottom and sides of the beaker. 



As the substance dissolved to an opalescent solution iu distilled water, it was washed with 

 50 per cent alcohol as long as with silver nitrate any chlorine was discoverable in the washings; 

 then the washing was continued with absolute alcohol and with ether, and the substance dried 

 over sulphiu'ic acid; 8.5 grams of substance were thus obtained. The salt solution from which the 

 spheroids had deposited was nextdialyzed, and the proteid which separated out on the removal of 

 the salts was filtered oft', M^ashed iu succession with dilute alcohol, absolute alcohol, and ether, and 

 dried over sulphuric acid. This preparation weighed 5.64 grams. 



