CHAPTER VII 



NEUTRALISATION OF DIPHTHERIA-TOXIN, RICIN, SAPO- 

 NIN, AND SNAKE-VENOMS 



IN very nearly the same manner as tetanolysin behaves 

 the practically most important of all toxins, namely, diph- 

 theria-toxin. Through the circumstance of its preparation 

 and standardisation upon a large scale, a great number of 

 experiments have been carried out with it. Unfortunately 

 in most of these experiments but a few (4-6) points in the 

 neutralisation curves have been determined, and no indica- 

 tions are given of the magnitude of the experimental errors. 

 This is, of course, due to the circumstance that we are still 

 in the first beginning of the development of the quantitative 

 side of this question. In a memoir in the Centralblatt fur 

 Bakteriologie (1903), p. 630 et seq., Madsen reported a 

 greater number of measurements of several preparations of 

 this toxin than had been generally done. As illustration 

 may be given the values for poison No. 471 in February- 

 March, 1902 (5 months old), and in November of the 

 same year (14 months old). The letters n and q corre- 

 spond, as for tetanolysin above, to the quantity of antitoxin 

 added and toxicity. 



As will be seen from these figures, the addition of the 

 first quantities of antitoxin seem not to diminish the toxicity 

 of the poison, the observed toxicity remains constant, and a 

 decrease of ^ obs- is not apparent until the quantities 0.05 

 respt. o.i 8 of antitoxin have been added. From this Mad- 



196 



