SUMMARY. 115 



proteins the intensity of its glyoxylic acid reaction was greater than that of 



any of the other proteins. 



L,eucosin also gave the strongest reaction with the Molisch test of any of a 



large number of different proteins examined under like conditions, but 



whether or not it contains a carbohydrate group must be shown by other 



evidence. 



THE GLOBULIN. 



The seeds of wheat contain about 0.6 per cent of a protein which is insol- 

 uble in water, but soluble in neutral saline solutions. This globulin is chiefly 

 contained in the embryo from which 5 per cent was extracted by sodium- 

 chloride solution. The preparations of the globulin that were made from 

 the embryo contained nucleic acid, while those from the whole seed con- 

 tained none. These nucleic acid compounds from the embryo behaved like 

 nucleates, for their proportion of nucleic acid was not constant, but varied 

 with the conditions of preparation. It seemed most probable that the nucleic 

 acid combines with the basic protein to form salts in the same manner as 

 other acids are known to do, and that such combinations with the globulin 

 still retained the solubility characteristic of the globulin. It is quite possi- 

 ble that other insoluble compounds containing more nucleic acid may have 

 existed in the embryo or have been formed during extraction, so that the 

 amount of globulin obtained may not have equaled that actually present in 

 the embryo. The fact that the globulin from the whole seed was free from 

 nucleic acid, while that from the embryo was not, was probably due to the 

 presence of a much larger proportion of protein insoluble in salt solution in 

 the whole seed compared with that in the embryo, so that the nucleic acid 

 united with the insoluble protein instead of with the globulin, as happened 

 when the embryo was extracted. 



This globulin is very similar to, if not identical with, that found in the 

 seeds of rye and barley. It contains over 18 per cent of nitrogen, and re- 

 sembles, in composition and properties, many of the globulins found in large 

 proportion in many other seeds. 



Owing to the difficulty encountered in preparing large quantities of this 

 globulin, the products of its hydrolysis have not been studied. 



Its ultimate composition is shown by the following figures, which are the 

 average of several analyses of preparations from the whole seed : 



P. ct. 



Carbon 5 x -03 



Hydrogen 6.85 



Nitrogen 18.39 



Sulphur o. 69 



Oxygen 23.04 



100.00 



