THE PROTEINS 41 



as piperazin rings and ester or ether groups, resulting 

 from the formation of intra-molecular anhydrides 

 dependent upon the presence in the oxy-amino- 

 acids of hydroxyls (OH' ions).* The formation of 

 protein is a complicated process, probably consisting 

 of a series of assimilatory additions to the molecule, 

 whereby the amino-acids form the peculiar com- 

 plexes under construction. " In the architecture 

 of the protein-molecule and its derivatives Nature 

 has attained her highest chemical performances." 



Where and how the formation of protein from 

 amino-acids takes place is not known exactly, but 

 there is evidence in vascular plants that it takes 

 place in the leaves. Emmerlingf favours the theory 

 that in plants the amino-acids are formed from the 

 simple inorganic nitrogen compounds which are 

 absorbed by the roots. The formation of asparagin, 

 leucin, and other amino-acids takes place chiefly in 

 the leaves. They are used in the synthesis of 

 albumin and other proteins ; but as time goes on 

 the amount produced is in excess of that required 

 for leaf-production, and is used up in the develop- 

 ment of seeds. In plants nitrogenous substances 

 travel in the form of amino-acids and amides from 

 one part to another. In their construction or trans- 

 formation from one grade to another ions are 

 doubtless formed and utilised for chaining groups 

 together. Ions are the vehicles of energy, whether 

 it be of the nature of electricity, chemical energy, 

 or a more subtle vital force, and their presence most 



* Prof. Barker's address at British Medical Association meet- 

 ing, Toronto, 1906. 



f Lander. Versucks.-Stat., 1900, liv., 215. 



