68 THE PROTEOMORPHlC THEORY AND THE NEW MEDICINE 



lets, there is reason to believe, are only extruded contents of red 

 corpuscles. 



It may fairly be concluded, then, that the hydrolyzing of poly- 

 peptids that find their way into the blood stream may be accom- 

 plished by enzymes secreted by various organs and tissues, includ- 

 ing the muscles; that the red blood corpuscles are very active 

 agents in this capacity, notably, perhaps, with regard to the 

 most complex polypeptids ; and that it does not fall within the 

 range of the activities of the leucocyte to deal with these com- 

 paratively simple nitrogen compounds. The leucocyte, like the 

 organs that produce the digestive ferment of the intestine, acts 

 on the full-sized protein molecule, and begins its cleavage. But 

 in the light of the new evidence, it may somewhat be doubted 

 whether the leucocyte is able to carry on this cleavage to its 

 final conclusion. It is at least possible that the protein molecules, 

 multiplied by cleavage, acquired an osmotic pressure that causes 

 the disruption of the leucocyte when the polypeptid stage of hy- 

 drolysis has been reached. If such is the case, the autolyzed 

 leucocyte would discharge its contents in the midst of myriads 

 of red blood corpuscles capable of taking up the work of hydro- 

 lysis where the leucocyte left it, and completing the cleavage of 

 polypeptids into amino-acids. 



According to the hypothesis already expounded, it would be 

 only comparatively small quantities of foreign protein that would 

 thus come under the auspices of the leucocyte ; but it is not un- 

 likely that considerable quantities of polypeptids may find their 

 way habitually into the blood stream ; and it is to be recalled 

 that the red corpuscles, marshaled in numbers not far from a 

 thousand times as great as the number of leucocytes, should be 

 able to deal with the polypeptids in almost any quantity. 



It is even conceivable that all the protein foodstuffs are ab- 

 sorbed in this state (since the evidence for their change into 

 amino-acids in the intestinal wall is not quite conclusive), and 

 normally undergo their final stages of hydrolysis under influence 

 of the erythrocytic enzymes ; the tissues of the liver and brain 

 and muscle standing guard meantime in the background, as it 

 were, ready to attack (each within the limits of its capacity) 

 any portions of polypeptids that escape the militant army of red 

 corpuscles. The numbers and aggregate bulk of the red cor- 

 puscles suggest their possible capacity to accomplish such a task. 



These experiments, then, enable us to form a more complete 

 and more satisfying mental picture of the processes of digestion 

 and assimilation than has ever hitherto been possible. We shall 

 be able to fill out certain gaps in the picture as we proceed, ulti- 

 mately presenting at least a suggestive scheme of the entire cycle 

 of protein metabolism in the body. 



