GALLUS SONNERATI. 45 



in a concentrated state, but dissolves it again when assisted by a 

 gentle heat, forming a solution of a very fine red colour. The 

 pure alkalies dissolve it, even when coagulated. In its natural or 

 uncoagulated state, the white of egg soon putrifies, unless it be 

 dried, when it assumes the appearance of horn, and may be kept 

 in this state for an indefinite time. It contains small portions of 

 free soda and sulphur, and hence it changes the vegetable blues to 

 a green colour, and blackens metallic silver. According to the 

 experiments of Dr. Bostock, white of egg consists of water 85.0, 

 albumen 1.2, in 100 parts; and besides shews traces of unco- 

 agulable matter 2.7, and salts 0.3, sulphuretted hydrogen gas, and 

 benzoic acid. The yolk, or vitcUus, is that well known spherical 

 yellow mass, which occupies the centre of the albumen ; it is 

 included in an extremely delicate membrane, which is apparently 

 without fibres, and is inelastic. In the common domestic fowl it 

 is inodorous, and has a bland sweetish oily taste. It mixes readily 

 with water, and forms a milky emulsion, which in France is 

 termed lalt de poule, or hen's milk. When heated it becomes 

 solid, and yields by expression a yellow insipid fixed oil. Its 

 principal constituents are water, oil, albumen, and gelatin ; on the 

 presence of the albumen depends the solidity of the boiled yolk, 

 and the oil which it contains forms a saponaceous liquid when 

 mixed with potash. Eggs may be preserved for a considerable 

 length of time, by covering them with grease or immersing them in 

 lime water, which prevents the admission of air through the pores 

 of the shell. A fresh egg is translucent, or semi-transparent, but 

 when it is opaque, or appears cloudy when placed between the eye 

 and the light, it must be rejected. 



Medical Properties and Uses. — The yolks of raw eggs are 

 said to be greatly laxative, and have been thought serviceable in 

 jaundice and obstructions of the liver. By the late Mr. White, 

 of Manchester, and Professor Hamilton, of Edinburgh they 

 have been highly extolled in the icterus of pregnant wo- 

 mne. In the form of emulsion, combined with mucilage and 

 syrup, they are sometimes employed as a demulcent in coughs, 

 hoarseness, and other pulmonary affections. Mixed with Rhenish, 

 or other light wine, and rendered grateful by the addition of lemon 

 juice and sugar, raw eggs are frequently prescribed in conva- 



