1 84 



MANUAL OF BACTERIOLOGY. 



with a toxin molecule as readily as when the receptor is still 

 attached to the cell. Such a detached receptor constitutes a 

 molecule of antitoxin. 



As the side-chains or receptors of the protoplasm are essential 

 to its existence, their combination with the toxin, through its 

 haptophore, results in destruction of the molecule. But if the 



damage be not too seri- 

 ous, the protoplasm is 

 stimulated to produce 

 numerous similar side- 

 chain groups — to an 

 overproduction of these, 

 in fact. As not all of 

 these are necessary for 

 the performance of its 

 functions, the superflu- 

 ous ones are thrown off 

 into the surrounding 

 serum. It is well known 

 that many cells of the 

 body exhibit analogous 

 heightened activities 

 under stimulating in- 

 fluences, as pointed out 

 by Weigert. If such free 

 side-chains or receptors 

 combine with the hap- 

 tophorous groups of the toxin, the latter is no longer able to com- 

 bine with the protoplasm of the cells. Thus they act as a kind 

 of buffer in protecting the protoplasm from the attacks of the 

 toxins. These free, cast-off receptors constitute the antitoxic 

 part of the se.um as stated. 



Numerous experiments have been made which illustrate 

 the probable chemical nature of antitoxin action. A fatal 



Fig. 48. — Receptors of the First Order 

 Uniting with Toxin. — {Journal oj the 

 American Medical Association. 1905. 

 P- 95S-) 



u. Cell receptor. 6. Toxin molecule, t. 

 Haptophore of the toxin molecule. 



d. Toxophore of the toxin molecule. 



e. Haptophore of the cell receptor. 



