THE CONSTITUENTS OF DIPHTHERIA TOXIN. 503 



cially Geh.-Rath Donitz and Dr. Morgenroth) and myself, have been 

 most exact, and I venture to say that in medicine but few investiga- 

 tions exist which have been carried out with such precision and on 

 such abundant material. 



II. Toxons. 



Thus far we have dealt only with the true toxin portion of the 

 diphtheria poison, and have entirely disregarded another constant 

 secretory product of the diphtheria bacillus, namely, the toxons. On 

 testing a diphtheria poison and determining the two limits, L and LJ, 

 we should expect that the difference, L-J--L =D, would correspond 

 exactly to one lethal dose, provided the poison were a simple uniform 

 substance. Thus if L , for example, contains a lethal doses these, 

 according to our definition of LQ, will exactly be neutralized by 

 1 I. E. Assuming that the two substances have a strong affinity for 

 each other, the addition of one L. D. would suffice to transform this 

 neutral L mixture into Lf, i.e., Lt should contain (a+1) L. D. and the 

 difference, D, should equal 1. As a matter of fact, however, it was 

 found that with the exception of one poison examined by me, the 

 difference between Lt and L is much greater. In the poisons de- 

 scribed in my first communications the difference D ranged from 

 5 to 50 L. D. At first, when I still held to the Unitarian conception, 

 I had interpreted these results as indicating the existence of a toxin 

 derivative of very little toxicity and possessing less affinity than the 

 toxin. For this reason I termed the derivative "epitoxoid." In my 

 second communication, however, I abandoned this assumption, and 

 stated that we were evidently dealing with a primary secretory prod- 

 uct of the diphtheria bacilli the "toxon." The reasons which led 

 me to this view will be presented in a moment. The toxon possesses 

 the same haptophore group as the toxin, but a weaker affinity for the 

 antitoxin. The main difference is in the toxophore group, for even 

 when given in large doses the toxon does not produce death, but only 

 paralyses which develop after a long incubation of fourteen days or 



more. 1 



Arrhenius and Madsen have doubted particularly the existence of 



1 It may be remarked in passing that such additional or "by-poisons" with 

 a long period of incubation are not limited to diphtheria bacilli. According 

 to the observations of Sclavo on animals infected with anthrax it is highly 

 probable that anthrax bacilli also produce poisons having a toxin-like action. 



