ANALYSIS OF THE WHITE. 363 



white of egg there is about 0*5^ of sugar (as calculated from the 

 carbonic acid developed after the induction of fermentation). 



The number representing the extractive matters of the white 

 after the deduction of the fat, the sugar, and the salts, is not large ; 

 I found 3'143 in its solid residue. 



It is worthy of notice, that a little albuminate of soda passes 

 over into the alcohol-extract as well as into the water-extract, if 

 we do not previously neutralise the white, and hence we may 

 readily obtain an apparently larger quantity of extractive matters ; 

 the acetic acid, in combination with the alkali of the alcoholic 

 extract, should consequently be deducted in the determination of 

 the extractive matters. 



Although the white of egg is a substance that falls under our 

 daily observation, there does not as yet exist any good analysis 

 of it; for certain precautionary measures are requisite for its 

 examination, which have not been sufficiently attended to. The 

 gelatinous white, as we obtain it from fresh eggs, is not merely an 

 albumen or an albuminate of soda swollen with water, together 

 with some adhering fat and an admixture of soluble substances, 

 but it likewise contains insoluble membranous parts ; we here 

 refer not only to the chalazse, but also to the delicate, textureless, 

 only faintly granular membranous structures which cross the 

 white in various directions, and so inclose it that, even after its 

 careful removal from the egg, it always retains the appearance of a 

 tolerably consistent mass. These delicate membranes possess the 

 same refractive power as the white that is inclosed within them ; 

 and hence they do not become visible till after the addition of 

 water. It must not, however, be supposed that all the flakes 

 which become separated on the admixture of water and white of 

 egg, are merely these previously invisible membranes, for the 

 albuminate of soda of the e^g, like that of the blood-serum, 

 separates by strong dilution with water into an albuminate rich in 

 alkali, and into albumen poor in alkali ; the latter increases the 

 insoluble part of the albumen that has been modified by water. 

 We may readily convince ourselves on this point, by the addition 

 of a neutral alkaline salt, as for instance, chloride of sodium or 

 hydrochl orate of ammonia, to albumen which has been thus 

 treated, and has become almost white and opaque from the 

 separated flakes; a very great part of the turbidity then dis- 

 appears, and we can now perceive, on a microscopic examination, 

 that the portion which still remains undissolved consists merely of 

 the prolongations of the chalazse and the membranous parts. Hence, 



