YOLK AND WHITE OF THE EGG. 157 



used. In order to dissolve the precipitate a much greater 

 addition of acid or heating of the solution is necessary (dis- 

 tinction from serum albumin). 



10. On shaking a small quantity of the solution with an 

 equal volume of ether, coagulation gradually takes place. 



11. On heating a small portion of the solution after the 

 addition of an equal volume of sodium hydroxide of 1 .34 

 specific gravity and about three drops of neutral lead acetate, 

 it turns black. The blackening is more pronounced than in 

 the case of serum albumin. If this solution is then acidified 

 with hydrochloric acid there results, not a turbid grayish- 

 yellow fluid as in the case of serum albumin, but coarse dark- 

 gray flakes precipitate, while the fluid becomes almost clear. 

 This distinction is due to the fact, first, that more sulphur is 

 split off from the egg-albumin, and, secondly, that the albu- 

 minate from the egg-albumin dissolves with more difficulty 

 in hydrochloric acid than the albuminate from serum albumin. 



The reactions of a solution ten times as dilute agree 

 entirely with those given for the correspondingly dilute 

 serum. 



II. Detection of Glucose. 



Shake up the white of a hen's egg with ten times its 

 volume of water (about 200 cc.), add acetic acid to neutral 

 reaction, and heat to vigorous boiling in a large evaporating- 

 dish over a free flame and with constant stirring (caution on 

 account of the strong foaming) until the albumin has sepa- 

 rated in lumps and the fluid appears quite clear. Then filter, 

 wash with some water, and evaporate the filtrate and the 

 wash -water over a free flame to a small volume, about 10 to 12 

 cc. Use half of this for the Trommer's test with sodium 

 hydroxide and copper sulphate solutions, and the other half 

 for the fermentation test. Both give positive results. 



