684 LECTURE XXX. 



With the above in mind, let us apply the side-chain theory to the forma- 

 tion of antitoxines. We have already stated that the bacterial poisons 

 are probably very closely related to the proteins. We can easily imagine 

 that they may have atomic groupings very analogous to those of the nutri- 

 ents, and that, for this reason, they are attached to distinct cells. The 

 cell immediately loses its ability to assimilate any nutrient material at 

 those points where any toxines have attached themselves. If the cell has 

 not been permanently injured by the poison, it will try to repair the damage 

 by a fresh supply of side-chains. Under these conditions there may be an 

 over-production of side-chains, to such an extent that they will not all have 

 room to attach themselves to the protoplasm; they will consequently be 

 pushed off, and circulate in the blood. We must not forget that these new 

 side-chains must correspond exactly in their composition to those to which 

 the toxines have attached themselves. This " first" side-chain must cer- 

 tainly have had a definite affinity for the toxine before it combined with it, 

 in its transport in the organism. 



Those analogously constituted side-chains which circulate in the blood 

 must also have the ability of uniting with toxines, thus making them 

 harmless, before they reach the cells. According to this view, the forma- 

 tion of antitoxines is not a new process the free side-chains are nothing 

 more than antitoxines but merely a repetition of a normal function of 

 the cell. It corresponds to the secretion of the individual cells to which 

 we have repeatedly called attention. It is impossible for us to go into the 

 details of the facts which go to substantiate Ehrlich's assumption. We 

 only wish to add that it has been shown that definite bacterial poisons, for 

 instance tetanus poison, enters into combination with tissue-cells, and 

 that, on the other hand, we are acquainted with poisons which can be recog- 

 nized as having very distinct affinity for specific tissues. Thus, it is 

 known that abrin possesses very close relationship to the components of 

 the tissues of the conjunctiva. Ehrlich designates the group of the toxine 

 molecule, which unites with the side-chains of the cells, or the free side- 

 chains, as the haptophor group. It is clear, if this conception of the com- 

 bination of toxines and antitoxines is correct, that only a definite amount 

 of the latter can combine with a given quantity of the former. The whole 

 process must evidently correspond to a neutralization. 



The toxine also contains a toxophor as well as a haptophor group. This 

 is the carrier of the specific poisonous effect of the toxine. That this 

 assumption of different groups in the toxine molecule is well founded fol- 

 lows from the fact that antitoxines may be produced even after the toxophor 

 group itself has been destroyed. It has, itself, nothing to do with the im- 

 munity reaction of the organism. In the latter case the haptophor group 

 only must be taken into consideration. If this be removed, for instance 

 by antitoxine, then the toxine will be rendered valueless for immunization. 



