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Dr. Paul Ehrlich. 



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 themselves, every group uniting with a correspond- 

 ing combining group of a side-chain. The relationship of the corre- 

 sponding groups, i.e., 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 contemplate the relation of the toxine to the 

 cell. 



We have already shown that the toxines possess for the antitoxines 

 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 

 toxine and cell ceases to be shrouded in mystery if we adopt the 

 view that the haptophore groups of the toxines are molecular groups, 

 fitted to unite not only with the antitoxines but also with the side- 

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

 becomes anchored to the cell. 



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

 fit with the haptophore groups of the toxines, i.e., the side-chains 

 which are toxophile, represent something 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 toxines 

 are, in opposition to other poisons, of highly complex structure, 

 standing in their origin and chemical constitution in very close rela- 

 tionship to the proteids and their nearest derivatives. It is, therefore, 

 not surprising if they possess a haptophore group corresponding to that 

 of a food-stuff. Alongside of the binding haptophore group, which 

 conditions their union to the protoplasm, the toxines 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 toxine there was reason to believe that there existed 

 alongside of the haptophore group another and absolutely independent 

 toxophore group. 



Now for certain cellular elements of the body it can be proved in 

 the test-tube that between these tissues and certain toxines an "anchor- 

 ing " process takes place exactly similar to that between toxine and 

 antitoxine. Wassermann first demonstrated this in the case of the 

 brain substance. In a mixture of tetanus toxine and broken-down 

 fresh guinea-pig brain the latter so bound or " anchored " the toxine 

 that not only was the surrounding fluid toxine-free, but the brain sub- 

 stance laden with the tetanus toxine had also lost its own toxic action, 

 and so the mixture when injected into an animal was borne without 

 any harm. 



