COLLEGE OF DENTISTRY 

 UNIVERSITY OF CALIFORNIA 



CHAPTER II 

 REVERSIBILITY OF REACTIONS BETWEEN ANTIBODIES 



As has been stated, many of the substances with which 

 we deal in sero-therapy are rather unstable. This insta- 

 bility is very different in different cases. Sometimes (e.g. 

 for snake-venom) the toxin is more stable than the anti- 

 toxin ; in other cases (e.g. for diphtheria and tetanus 

 poison) the converse holds true. The snake-venom resists, as 

 Calmette showed, an elevation of the temperature to 68 C., 

 which, however, destroys its antitoxin, the antivenin, in 

 aqueous solution. This circumstance was used by Calmette l 

 to separate the poison from the antivenin; after heat- 

 ing a mixture of the two a poisonous solution remained. 

 According to more recent investigations of Martin and 

 Cherry 2 this experiment is not successful if the mixture 

 is held at the temperature of the room for more than thirty 

 minutes before the heating is done. 



As Martin and Cherry intimate, the simplest explanation 

 of this behaviour is that the snake-poison and the anti- 

 venin require a certain time to react with each other. 

 Hence if the mixture is heated to 68 for ten minutes before 

 the reaction has practically reached the end-value, the free 

 antivenin is destroyed and after the heating the mixture 

 contains some free poison. 



1 Calmette : Ann. de rinst. Pasteur, 8. 275 (1894); Compt. Rend, de 

 VAc. de Sc. 134, No. 24 (1902). 



2 Martin and Cherry : Proc. Roy. Soc., 63. 420 (1898). 



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