﻿80 FREER. 



diphtheria toxin in guinea pigs which were simultaneously injected 

 with minimal doses of pure hydrocyanic acid, acting on the theorjr that 

 this substance, which so markedly "poisoned" Bredig^s colloidal inorganic 

 catalyzers, would do the same with the organic ones, and that hence the 

 action of the diphtheria toxin should be delayed, with a gradual recovery 

 of virulence as the hydrocyanic acid disappeared. The results were 

 entirely negative. However, this one series proves nothing excepting 

 that other means of experimentation must be resorted to. The work 

 could probably be more successfully carried out in vitro. 



The process of cell destruction by aid of the complements which are 

 present in the serum has one interesting phase which causes it to differ 

 from that where the catalytic agent, if I may use the term, is a chemical 

 individual which can be isolated, such as lecithin. In the case of the 

 serum complement there is a time of incubation — that is, the reaction 

 proceeds with an increment of increase in unit time — which can only be 

 brought about by the relatively increasing amount of catalyzer present, 

 in other words, the complement must either be formed during the reaction 

 or it must be liberated as soon as its work is done, but in the latter event, 

 in vitro; we must also have a steadily diminishing amount of substance 

 in unit volume to be acted upon, and a consequent gradual retardation. 

 The study of the rate of these reactions and the resulting curves is 

 therefore of fundamental importance, and in the case of hemolysis 

 the experimental difficulties would not seem to be too great to overcome. 

 It would certainly be well to determine the proportion of complement 

 and immune body as compared with that originally present remaining 

 in hgeinolyzed blood after the reaction is complete, although in this 

 connection care must be exercised not to confuse the possible effects of 

 substances like lecithin, which could be separated from the stroma, with 

 the true serum complements. 



In closing I wish to call attention to one phase of the researches on 

 immunity which would repay further investigation. Ehrlich has said : 



I accept the existence of haptophore groups exclusively in compounds such as 

 the food stuffs which can enter into the composition of the protoplasm or which, 

 such as the great series of poisonous or not poisonous products of the metabolic 

 changes of living cells, can enter into a combination similar to that of the food 

 stuffs. 



The deep-seated difference between the alkaloids, glucosides or medicinal agents 

 of known chemical constitution and those substances which possess haptophore 

 groups and which are therefore capable of liberating antibodies during the process 

 of immunization is shown by the fact that none of the former class have ever 

 been able to give rise to any antibody production of consequence. 



However, I believe that this seemingly impassible gulf can be crossed. 

 Undoubtedly, we can place on one side poisons from which no trace of 

 an immunity reaction can be secured and on the other substances, the 

 products of life action, which give all the typical phenomena which 



