Chapter I: SIMPLE PROTEIDS.--A. Soluble in water.--a. Coagulable by heat,

and by long contact with alcohol. Albumins: serum-albumin, egg-albumin, lacto-albumin, myo-albumin, vegetable albumins. _b._ Non-coagulable by heat and by long contact with alcohol. Proteoses:[51] protoproteoses, deuteroproteoses. Peptones:[51] amphopeptones, antipeptones, hemipeptones.

[51] Used in the generic sense; the proteoses including albumoses, globuloses, myosinoses, elastoses, etc., and the peptones the peptone-products formed in the digestion of any or all proteids.

_B._ _Insoluble in water, but soluble in salt solutions._--_a._ More or less coagulable by heat. Globulins. 1. Soluble in dilute and saturated NaCl solutions. Vitellins. 2. Soluble in dilute NaCl solutions, but precipitated by saturation with NaCl. Myosins, paraglobulin[52] or serum-globulin, fibrinogen, myo-globulin, paramyosinogen, cell-globulins. _b._ Non-coagulable by heat, soluble in dilute NaCl solution and precipitated by saturation with NaCl. Heteroproteoses.

[52] Not completely insoluble in saturated NaCl solution.

_C._ _Insoluble in water and salt solutions, soluble in dilute alcohol_--Zein, gliadins.

_D._ _Insoluble in water, salt solutions and alcohol; soluble in dilute acids or alkalies._--_a._ Coagulable by heat when suspended in a neutral fluid. Acid-albumins, alkali-albumins or albuminates. _b._ Non-coagulable by heat when suspended in a neutral fluid. Antialbumids, dysproteoses, glutenins.

_E._ _Insoluble in water, salt solutions, alcohol, dilute acids and alkalies; soluble in strong acids, alkalies, and in pepsin-hydrochloric acid and alkaline solutions of trypsin._--Coagulated proteids, fibrin.[53]

[53] In blood-fibrin we have a good illustration of the fact that these divisions are not absolutely exact, since this form of proteid matter, for example, is somewhat soluble in dilute acids and in salt solutions, although requiring a long time for marked solution.