MECHANISM OF PROTEIN HYDROLYSIS AND IMMUNIZATION 77 



case this cannot be accomplished, the protein which might, under 

 other conditions, be invaluable as food for the tissues becomes a 

 menace through a mechanical clogging of the spaces about the 

 cells, and perhaps through the accumulation of partially meta- 

 morphosed product as the result of the activity of the leucocyte. 

 Antibodies quite different from antitoxins will be developed by 

 the leucocytes; but, of course, these can avail only if the foreign 

 proteins come in relatively limited quantity. 



Making an anticipatory therapeutic application, it is clear that 

 the ideal to be aimed at when proteins are introduced hypodermi- 

 cally (as in Proteal therapy), is to give the dose that will evoke 

 a maximum corpuscular response with a minimum introduction of 

 foreign proteins that must themselves be proteolyzed. Whether 

 this may best be accomplished by using a single foreign protein 

 or by combining a number of such proteins is an important prac- 

 tical question that will be discussed later in this volume. 



So much by way of recapitulation, and to make clear the dis- 

 tinction that I conceive to exist between the sources and the 

 character of the antibodies as evoked by antigens that on one 

 hand are protein bodies and on the other are the metamorphosed 

 products of protoplasmic activity so-called toxins. 



THE COALITION BETWEEN RED CORPUSCLES AND WHITE 



Reverting now to the latter, in continuance of the theme, it 

 remains only to point out that, whereas it is conceived that all 

 the cells of all the tissues of the body have capacity for the 

 production of antitoxins in response to small moleculed toxins, 

 it would appear that there is one type of cell that is pre-eminently 

 adapted, by virtue of its location in the organism, to absorb these 

 toxins and render them innocuous ; at the same time, of course, 

 giving out the residual products which we term antitoxins. The 

 cells in question are the red corpuscles of the blood. 



A very prominent function of these cells, according to the pres- 

 ent thesis, is thus to shield the body-cells in general against the 

 attacks of the numerous toxins that necessarily, under existing 

 conditions, find their way more or less continuously into the blood 

 stream. In particular, to shield the brain cells, because they take 

 (in Abderhalden's experiments) the same type of complex nitro- 

 gen compounds that have affinity for the cerebral tissues. Ordi- 

 narily the red corpuscles come in contact with them first, and 

 thus the brain is protected. 



As justification for the conclusion, we have the entire line of 

 analogical reasoning just presented, supported specifically by the 

 experiments of Abderhalden, which showed, it will be recalled, 

 that the red blood corpuscles manifested exceptional activity in 



