IMMUNITY AND THE POWER OF DIGESTION. 1 



VERA DANCHAKOFF, 

 COLUMBIA UNIVERSITY. 



The proteins are the fundamental chemical constituents of the 

 living protoplasm in all our tissues and organs. But the cells of 

 the tissues do not take up the proteins as such, they are known to 

 live on the products of protein digestion, on their building stones, 

 the various amino-acids. And by a long process of synthetic 

 character the cells of a multicellular organism build up out of 

 these building stones their own individual proteins of a highly 

 specific structure. 



The multicellular organism possesses special organs of digestion 

 which successfully perform the work of splitting the ingested 

 food to the stage of amino-acids, in which stage they become 

 capable of passing through the intestinal wall ; they are absorbed 

 here and transported to all our tissues, which in this manner are 

 provided with various substances for their synthetic work in 

 order to replace the wear and tear of the living substance during 

 adult life or to build up organs and tissues during developmental 

 stages. 



Now are the cells of all our organs and tissues which, under 

 usual conditions, are supplied for their synthetic work with ready 

 made building stones, without one of the most characteristic and 

 important properties of the living matter, viz., the power of 

 splitting the chemically more complex proteins to the stage of 

 amino-acids? Or are these cells not manifesting a digestive 

 potency inherent in them, because they have no chance of 

 manifesting it, because the ingested food does not reach them 

 primarily and undergoes the hydrolytic changes before it is 

 capable of being absorbed? Is it a lack of power or a lack of 

 opportunity which prevents the cells of our tissues from mani- 

 festing a digestive capacity under usual conditions? 



1 Given at the meeting of the Section of Biology, New York Academy of Sciences, 

 October 13. 1919. 



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