TOXINS. 37 



structure so complicated it is easy to conceive of an asymmetrical 

 atomic arrangement of the toxophorous complex, and this is more 

 easily comprehensible on the assumption of the existence of the two 

 modifications (a and j8) in the same amounts. 



11. The haptophorous group, which under ordinary conditions is 

 quite stable, can be broken down by the action of strong chemicals 

 and certain physical agents (heat, iodin, etc.). 



12. The anti-bodies combine exclusively with the haptophorous 

 group and thus absorb the toxic molecule, so protecting the organism. 

 In this way the poison may be rendered harmless without destruction 

 of the toxophorous complex, 



13. It follows from what has been said that specific antitoxins can 

 be produced not only with toxins, but also with toxoids ; indeed, 

 highly susceptible auimals (mice and guinea-pigs), can be immunized 

 against the tetanus toxin safely and easily by means of toxoids. It is 

 probable that in this case the degree of immunity cannot be made 

 so great as is desirable in the preparation of a curative serum. How- 

 ever, it is possible that immunization with toxoids can be used di- 

 rectly for curative purposes, inasmuch as by this means an active 

 immunity may be brought into existence. 



14. In natural immunity, also in that form which is induced by 

 the bacterium itself and not by the bacterial poison, the toxons prob- 

 ably play a very important r6le ; while the toxoids do not exist in 

 these cases since they result only from the decomposition of toxins. 

 It is also probable that the artificial immunity which may be induced 

 by the simultaneous employment of an antitoxic serum and living 

 bacteria (as in rinderpest and swine erysipelas), and which is quite 

 lasting and is produced without marked disturbances of health, is in 

 great part due to the action of toxons. 



As has already been stated, the above-mentioned theory concern- 

 ing the constitution of toxins is founded upon experimental studies 

 of the action of toxins and antitoxins in the animal body, and does 

 not rest upon chemical experimentation ; indeed, Ehrlich expresses 

 the opinion that many decades must pass before we shall be able to 

 isolate the toxin chemically. We shall have opportunity later on in 

 our studies of toxins, antitoxins and immunity, to return to Ehrlich's 

 theory.* 



•See Chapter VII. 



