GALLUS DOMESTICUS. 



IV. The yelk forms an opaque emulsion when agitated by 

 water. When long boiled, it becomes a granular solid, and 

 yields by expression a yellow, insipid fixed oil. It consists of 

 four constituents, water, oil, albumen, and gelatine ; on the 

 presence of the albumen depends the hardness of the boiled 

 yelk. 



Eggs are applied to various purposes in medicine and phar- 

 macy. The shells, powdered and levigated, may be used ben- 

 eficially as an antacid in diarrhoea. In common with oyster- 

 shells they possess the advantage of uniting intimately ani- 

 mal matter with the carbonate of lime, the particles of which 

 are thus more thoroughly isolated, and prove more acceptable 

 to the stomach, than chalk, in the finest state of division to 

 which the latter can be brought by mechanical means. The 

 dose and mode of preparation are the same with those of 

 oyster-shell. 



The white of the egg is used chiefly for the clarification of 

 liquids, which it affects by involving, during its coagulation, 

 the undissolved particles, and rising with them to the surface, 

 or subsiding. When the liquid to be clarified does not spon- 

 taneously coagulate the albumen, it is necessary to apply heat. 

 It is recommended as an antidote for corrosive sublimate and 

 sulphate of copper, with which it forms insoluble and com- 

 paratively inert compounds. It is sometimes also used for the 

 suspension of insoluble substances in water, but is inferior foi 

 this purpose to the yelk, and even to mucilage of gum Arabic. 

 Agitated briskly with a lump of alum it coagulates, at the same 

 time dissolving a portion of the alum, and thus forming an 

 astringent poultice, advantageously applied between folds of 

 gauze over the eye, in some states of ophthalmia. 



The yelk in its raw state is gently laxative, and has been 

 thought serviceable in jaundice and other hepatic obstruc- 

 tions. Beaten up with sugar and wine, it is extremely nutri- 

 tive, and is consequently useful in convalescences and other 

 cases of debility. 



As an article of food eggs are the least stimulating of ani- 

 mal substances ; and the broth made of the young chicken is 

 not only the best restorative diet for the convalescent, but is 

 also a useful diluent in cholera, dysentery, and other disorders 

 of the bowels. After they are a year old, their flesh becomes 

 less and less digestible ; but the capon and poulard retain their 

 tenderness longer. 



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