﻿MODERN THEORIES IN RELATION TO IMMUNITY. 79 



I have mentioned above that, under undisturbed conditions of equilib- 

 rium the immune bodies or similar substances are undoubtedly 'con- 

 stantly being given off. I had in mind some of the phenomena of organic 

 chemistry in which the change of one stereochemical form into another 

 is brought about, or perhaps more aptly, the alterations which we observe 

 from the keto- to the enol-form and vice versa. We have bodies, for 

 example, which when prepared under certain circumstances, react like 

 ketones or aldehydes, these same bodies may spontaneously or under 

 slight stimulus, become altered to unsaturated alcohols and again under 

 others they may at times appear as ketones and at others as alcohols. The 

 same condition may apply when the equilibrium of the living body cell 

 is disturbed by the introduction of the foreign one — the immune bodies 

 which are normally proliferated may be changed in this manner in their 

 chemical structure by the introduced cell so that now they become 

 capable of independent existence and possibly also of firmer union with 

 other cells and so that they are also able to fix the complement. This view 

 does not seem improbable when we consider that we have immune bodies 

 of apparently similar origin, some of which are capable of firm fixation 

 to the introduced cell, others of which are but loosely bound and still 

 others which have their avidity increased by union with the complement. 



While I have shown above that the immune bodies may be produced by 

 catalysis of normal processes, it does not follow that they are themselves 

 catalyzers when they unite with the introduced cell, with the toxin, or 

 in the case of toxins themselves, with the body cell, for it has conclusively 

 been shown that such union does take place and that then these bodies 

 are either removed from the serum or that they unite with the toxin. 

 But, if the view of catatysis is correct, them these bodies, when so 

 attached should, at a very slow rate of reaction, accomplish that which 

 they do rapidly under the influence of the complement, for the catalyzer 

 simply accelerates an otherwise normal reaction ; in other words, to select 

 an example from the phenomena of haemolysis, the lysis of a red blood 

 cell to which an immune body is attached, should take place very slowly 

 as a normal reaction, which would proceed very rapidly to an end equi- 

 librium by the addition of the complement. Individual test-tube experi- 

 ments in haemolysis have not extended over a sufficient period of time 

 to prove or disprove this view, and it would be interesting to follow out 

 this subject if the experimental difficulties are not too great. 



On the other hand the complement which is attached to the ambo- 

 ceptor, either permanently, as in the case of the toxins, or which is 

 taken up from the blood serum, as with the heemolysins, seems much more 

 closely to resemble the catalyzers, but if it is a catalytic agent it must 

 accelerate a reaction which otherwise would take place with extreme 

 slowness, with such slowness, indeed, that without such a catalyzer no 

 noticeable difference of the normal equilibrium would take place. Dr. 

 Strong, acting on this view, has conducted a series of experiments with 



