224 THE INCOME OF ENERGY 



tion the chemical union between these atom groups 

 and the toxine is complete and the antitoxine is shut 

 out. Wassermann l found that when tetanus toxine 

 was mixed with fresh brain or cord substance from the 

 guinea-pig, the toxine united chemically with the nerve 

 centres so that neither the surrounding liquid nor the 

 mixture itself was poisonous when injected into an 

 animal. 



The stable benzene ring and the less stable side-chains 

 of the benzene derivatives 2 suggested to Ehrlich that 

 living cells also consist of a stable centre and less stable 

 side-chains. The side-chains enable the cell to form 

 chemical combinations with food stuffs and other bodies 

 that possess atom groups having a chemical affinity 

 with the atom groups in the side-chains. It is in this 

 way that the toxine is bound to the cell. Experiments 

 have shown that the binding atoms in the toxine 

 molecule are not the poison atoms. If for a portion 

 of fresh toxine there be determined quantitatively (1) 

 the killing power and (2) the amount of antitoxine 

 required to neutralize the toxine, and if the remainder 

 of the toxine be then allowed to stand for a time, it 

 will be found, on again determining the toxic power 

 and the combining power, that the toxic power has di- 

 minished, while the combining power remains almost 

 the vsame. Hence, two separate and independent groups 

 exist. Ehrlich terms the combining atoms the hapto- 

 phore group, while the poison atoms are the toxophore 



1 Wassermann : Berliner klinische Wochenschrift, 1898. 



2 See page 216. 



