34 THE PROTEOMORPHIC THEORY AND THE NEW MEDICINE . 



fact that the leucocyte is demonstrated to be able to deal with 

 complex proteins, inasmuch as it is observed to engulf and assim- 

 ilate protein-bearing bacteria in toto. 



That the leucocyte actually performs this feat, was first dem- 

 onstrated by MetchnikofT, and has been re-demonstrated thou- 

 sands of times over in recent years, notably by the students of 

 vaccine therapy. But the significance of this phenomenon, in 

 its broader aspects, although at least partially conceived by 

 Metchnikoff himself, was largely overlooked by his successors. 



It must not be understood, however, that the capacities of the 

 leucocyte as a proteoclastic agent have been altogether ignored 

 by recent workers. On the contrary, it is probable that some 

 of the physiological chemists have ascribed to the leucocyte in 

 this connection a larger measure of activity than it actually exer- 

 cises. Thus Hofmeister, stimulated no doubt by the discoveries 

 of MetchnikofT, was led to ascribe to the leucocyte the all- 

 important function of taking up the peptone believed (errone- 

 ously) to be absorbed through the intestinal wall, and converting 

 it into protein either directly or with the aid of the adenoid 

 tissues, thus making it available for assimilation by the body cells 

 in general. 



The peptone molecule, it will be recalled, is a cleavage product 

 developed from the original protein molecule of a food protein 

 hydrolyzed through the agency of the digestive ferments of stom- 

 ach, upper intestine, and pancreas. The molecule of peptone has 

 a molecular weight of only about four hundred, being therefore 

 about one-fortieth the size of its parental protein molecule. To 

 conceive that the leucocyte habitually takes this relatively small 

 molecule as its building stone and elaborates the complex pro- 

 tein molecule the molecular weight of which runs high into the 

 thousands and does this in case of all the protein that the 

 body utilizes is to make an assumption that at the least seems 

 amazing. 



Yet Hofmeister thought that he found justification for this 

 assumption in the fact that there is a marked postprandial leuco- 

 cytosis. If the leucocyte does not perform the function of com- 

 pleting digestion of the food and facilitating assimilation, he 

 argued, why should the number of leucocytes be habitually in- 

 creased after a meal? 



His reasoning seemed so valid that he has a good many fol- 

 lowers. Cramer and Pringle, for example, and Noel Paton be- 

 lieve that the leucocyte plays a very important part in the assim- 

 ilation of the protein food-products; and Pavy elaborated the 

 hypothesis, arguing that the entire conversion of the food pep- 

 tones into body protein is brought about by the leucocytes. 



The particular type of leucocyte believed to be chiefly involved 



