160 COMPOSITION OF THE BODY 



ties given above. A third class, the albuminoids are, in general, 

 particularly insoluble. 



The simple vegetable proteids may be divided roughly into six 

 classes according to their varying solubilities. 



I. Albumins. These are proteids soluble in water. They are 

 not precipitated from solution by sodium chloride, magnesium 

 sulphate or acetic acid. They are coagulated by heat at from 65 

 to 70 C. Leucosin from barley is an example of a vegetable 

 albumin. 



II. Globulins. This proteid is insoluble in water, soluble 

 in a dilute solution of sodium chloride, but is partly or completely 

 precipitated by saturation with the same salt. They are of two 

 kinds, myosins and paraglobulins. The former coagulate at 55 

 60 C., but the latter at a higher temperature, /o-75 C. Of this 

 class are tuberin (from the potato), vitellin (from maize), and 

 edestin which is found in many seeds. 



III. Albuminates (acid or alkali albumin), are soluble in dilute 

 acids or dilute alkalies, and precipitated from such solution by 

 neutralization. They are insoluble in water or neutral saline 

 solutions. The principal vegetable albuminates are conglutin 

 and legumin. The latter is a " vegetable casein " and occurs 



mostly in leguminous seeds. 



IV. Coagulated proteids are proteids that have been made less 

 soluble by heat, or chemical reagents, such as alcohol, or ferments. 

 They are hydrolyzed and dissolved by proteolytic ferments. They 

 are insoluble in water, saline solutions, dilute acids and dilute 

 alkalies. 



V. Proteoses. This term includes albumoses (from albumin), 

 globuloses (from globulin), etc. These bodies are intermediate 

 products in the hydrolysis of proteids. They are soluble in 

 water, saline solutions and acids ; they are precipitated by satura- 

 tion at boiling temperature with neutral ammonium sulphate. 

 They are non-coagulable. The vegetable proteoses are called 

 phyto-proteoses. 



VI. Peptones. These are the final products of the hydration 



