ALBUMEN. 181 



men were reduced in one case to 10-15, and in another to 14*28 

 parts.* 



It has not hitherto been possible to free albumen from all fo- 

 reign matters ; but it is brought to a state approaching purity by 

 the following process : 



Mix the white of eggs with a considerable quantity of distilled 

 water, and rub the mixture intimately in a glass or porcelain 

 mortar, to break down all the membranous cells in which the 

 albumen is lodged, and allow it to dissolve in the water. Throw 

 the whole on a filter of very bibulous paper, and raise the tem- 

 perature of the filtered liquor to 160. The albumen will coa- 

 gulate in white flocks. Let it subside to the bottom of a cylin- 

 drical glass in which the whole liquid has been put. Draw off 

 the clear liquid, and add a new portion of distilled water. Agi- 

 tate well, allow the albumen again to subside, and draw off the 

 water a second time. This process may be repeated a third time, 

 after which the albumen is to be dried in a gentle heat. Reduce 

 it to a fine powder, digest it in alcohol till that liquid ceases to 

 dissolve any thing. Finally, dry it over the steam-bath. It is 

 now as pure as it is in our power, with our present knowledge, to 

 make it.| 



Albumen purified in this manner, when burnt, leaves about 

 2 per cent, of a gray-coloured ash ; doubtless, the earthy salts 

 (chiefly phosphates) which the white of egg contained. Scheele 

 observed, that when the white of an egg was dissolved by boiling 

 it in very dilute acids, it was again precipitated by adding some 

 concentrated acid. During this precipitation a smell of sulphu- 

 retted hydrogen was perceptible, showing clearly that it contains 

 sulphur.J 



Albumen prepared in this way is transparent, and has an 

 amber colour. When put into water it swells up, becomes opaque 

 and white, and assumes the appearance of coagulated white of 

 egg. According to Chevreul, 1000 parts of water dissolve 7 

 parts of coagulated albumen. 



It dissolves in concentrated muriatic acid, and the solution, as 



* Neumann's Chemistry, p. 554. 



f It will not be freed from soda nor from the earthy phosphates which may 

 have existed in white of egg. To get rid of these it must be treated with an 

 acid. 



J Scheele's Chemical Essays, p. 268. 



