CLASS II. Derived albumens (albuminates).
1. a solution of native albumen is acted on for a time with dilute hydrochloric acid (or some other) it becomes changed in properties; it is uo longer coagulable by heat; when the solution is carefully neutralized the albumen is completely precipitated. The proteid in this case becomes converted into what is called acid-albu men, whose characteristics are insolubility in distilled water and in solutions of common salt and other neutral salines, but readily soluble in dilute acids as well as alkalies; and such solutions are not coagulable by boiling. If finely-chopped muscle, from which the soluble albumens have been removed, is treated for a considerable time with a .2 per cent solution of hydrochloric acid, most of the muscle becomes dissolved, the trans parent solution containing a proteid which closely agrees inmost characteristics with acid-albumen, and is called syntonia (q.v.).
2. Alkali-albumen.-11 serum, or egg albumen, is treated with a dilute alkali, a change similar to that which occurred with treatment by acid takes place, and the albu men is no longer coagulable by heat, and precipitation follows neutralization. Indeed, the two preparations seem to be of the same nature, and one may be substituted for the other in subsequent experiments. The rotatory power of alkali-albumen varies according to its source. When it is prepared by strong caustic potash from serum-albumen, the rotation increases from 56° (that of simple serum-albumen) to 86°. When prepared from egg-albumen it is 47° instead of 35.5° (that of simple egg-albumen). It pre pared from coagulated white of egg the plane of polarization will be turned 58.8°. It is therefore supposed that there are several forms of alkali-albumen 3. Cuseine. This proteid exists in milk. See CASEINE.