THE PROTEIN SUBSTANCES. 89 



A peculiar protein body known as zein, or maize fibrin, is 

 found in corn meal. It is soluble in alcohol but not in water, 

 and is not soluble in dilute alkali solutions. Corn contains 

 also three globulin-like bodies and one or more substances to 

 be classed with the albumins proper. 



Edestin is a characteristic crystalline phytovitellin found 

 rather widely distributed, but most readily prepared from 

 hemp seed and squash seeds. 



Legumin is found in peas, beans and related seeds ; it 

 belongs to the group of nucleo-albumins, but in its solubility 

 conditions resembles the typical globulins. The legumin ob- 

 tained from vetches does not coagulate on boiling. On boiling 

 a solution of pea legumin a jelly-like substance is formed. 



Other Nucleo-albumins. In the eggs of fishes there is 

 found a peculiar vitellin called ichthulin, which has been 

 obtained in crystalline form. It is not soluble in water, but 

 yields a clear solution with weak alkalies. 



In cell protoplasm several different nucleo-albumins are 

 found. These bodies contain iron, are insoluble in water in 

 pure condition, but with alkalies form salts which are readily 

 soluble. 



TRANSFORMATION PRODUCTS. 



The protein bodies which have been described in the fore- 

 going pages are natural unmodified substances or primary 

 products. We have now to consider briefly a class of impor- 

 tant protein compounds which includes secondary or modified 

 substances which in the main are derived from the native albu- 

 mins just discussed. These modified forms may be obtained 

 in various ways, but for convenience three groups of transfor- 

 mation products may be made, as shown below. 



COAGULATED OR MODIFIED ALBUMINS. 



It has been shown already that white of egg dissolves easily 

 in water. The solution so made undergoes a change when 

 heated or when treated with certain reagents. This change is 



