The "Lateral-chain Theory" of Immunity 135 



may differ from one another according to the requirements 

 of the different cells. And as these side-chains have the 

 office of attaching to themselves certain food-stuffs, we must 

 also assume an atom-grouping in these food-stuffs them- 

 selves, every group uniting with a corresponding combining 

 group of a side-chain. The relationship of the correspond- 

 ing groups, i. c., those of the food-stuff, and those of the cell, 

 must be specific. They must be adapted to one another, 

 as, e. g., male and female screw (Pasteur), or as lock and 

 key (E. Fischer). From this point of view, we must con- 

 template the relation of the toxin to the cell." 



"We have already shown that the toxins possess for the 

 antitoxins an attaching haptophore group, which accords 

 entirely in its nature with the conditions we have ascribed 

 to the relation existing between the food-stuffs and the cell 

 side-chains. And the relation between toxin and cell ceases 

 to be shrouded in mystery if we adopt the view that the 

 haptophore groups of the toxins are molecular groups fitted 

 to unite not only with the antitoxins, but also with the side- 

 chains of the cells, and that it is by their agency that the 

 toxin becomes anchored to the cells." 



' ' We do not, however, require to suppose that the side- 

 chains, which fit the haptophore group of the toxins, that 

 is, the side-chains which are toxophile, represent some- 

 thing having no function in the normal cell economy. On 

 the contrary, there is sufficient evidence that the toxophile 

 side-chains are the same as those which have to do with the 

 taking up of the food-stuffs by the protoplasm. The 

 toxins are, in opposition to other poisons, of extremely 

 complex structure, standing in their origin and chemical 

 constitution in very close relationship to the proteids and 

 their nearest derivatives. It is, therefore, not surprising 

 that they possess a haptophore group corresponding with 

 that of a food-stuff. Alongside of the binding haptophore 

 group, which conditions their union to the protoplasm, the 

 toxins are possessed of a second group, which in regard to 

 the cell is not only useless, but actually injurious. And we 

 remember that in the case of the diphtheria toxin there was 

 reason to believe that there existed alongside of the hapto- 

 phore group another and absolutely independent toxophore 

 group." . . . . "As has been said, the possession of a 

 toxophile group by the cell is the necessary preliminary 

 and cause of the poisonous action of the toxin." .... 



