ALBUMEN.

89

bodies of animals, and which are therefore called proxi-mate animal principles, are, albumen, gelatin, fibrin,and fat, or oily substances ; besides these, chemists havedetected a multitude of other substances; but theseare the most important, or those which constitute thegreater bulk of animal matter.

271. There are many varieties of albumen and fibrin,which, in consequence of peculiar properties or slightdifferences in composition, have received different names;it is unnecessary to study the nature of all these sub-stances ; we may include them under the general termsalbumen and fibrin.

272. Albumen is a white solid substance, whichswells up and dissolves in water, forming a clear trans-parent solution. Albumen is separated from its solutionin water by the addition of certain acids, and also bythe action of heat ; when a clear solution of albumen isboiled, the albumen separates in the form of a whitecurd or scum.

273. This substance exists in many parts of theanimal system. The white of egg consists of hardlyanything else ; when a fresh egg is boiled, the albumenseparates as a white curd; it coagulates, or becomesinsoluble in water. Albumen occurs, in a state of solu-tion, in blood and many of the liquids and softer partsof animal bodies. It is also found in a dry or solidform.

274. Dry albumen may be kept for a long time with-out undergoing decomposition; but in solution, or when