510 COLLECTED STUDIES IN IMMUNITY. 



large content of toxon. The spectrum, which corresponds to the 

 curve obtained by the authors, is here reproduced (Fig. 3, Phase II). 



From this we see that a zone of hemitoxin in the beginning of the 

 spectrum is followed by a zone of almost pure toxin, and this in turn 

 by a zone of tritotoxin-toxoid. Then comes the very long toxin 

 fraction. 



To one employing this mode of representation, such a spectrum 

 not only pictures the present constitution of the poison but also 

 frequently permits him to reconstruct its previous constitution. 

 In this case, for example, it was possible to do so with the aid of 

 several statements by the authors concerning earlier and later stages. 

 According to these figures I would assume that in the first phase 

 the poison contained a pure toxin in the initial zone. In the second 

 phase, the period at which the poison was studied by Dreyer and 

 Madsen, this had become transformed into hemitoxin. In the third 

 phase it may become pure prototoxoid. A fourth phase would then 

 show the transformation of the pure toxin in the above spectra into 

 hemitoxin and the poison would then have reached the point which 

 we have so frequently observed in other poisons. The spectra of 

 these various phases is as follows (Fig. 7) : 



I shall now present the figures which Madsen and Dreyer ob- 

 tained when they started with double the L dose (0.1 cc. poison). 

 In the first phase, their statement that the lethal dose was 0.0015 cc. 

 shows that 0.1 cc. poison contains 66 L. D. Calculation from the 

 spectrum gives 65 L. D. 



The second phase, of course, agrees entirely with the statements 

 of the authors, since the spectrum was constructed according to these. 



In the third phase the formation of the prototoxoid zone from 

 the previous zone of hemitoxin is readily seen from a second neu- 

 tralization test, one made with normal horse antitoxin. 



In phase IV the lethal dose had risen to 0.0027, corresponding 

 to 37 L. D. in 0.1 cc. Calculating this from my spectrum I obtain 

 35 L. D., which is but 2 L. D. smaller than would correspond to 

 the final stage. Perhaps this stage had been nearly but not yet 

 completely attained. It is probable that if the examination had 

 been made a little later the figure would have been exactly 35. 



The figures obtained from my reconstructed spectra harmonize 

 so well with those obtained experimentally by the authors that it 

 seems almost impossible to doubt the correctness of my assumptions 

 concerning the constitution of the poison and the process of its trans- 



