9 
The school founded by Ehrlich ^ in 1897, based on Ins scholarly 
work upon the constituents of the diphtheria poisons, and methods 
of standardizing the antitoxic value of the curative serum, made 
much use of the post-diphtheritic paralyses produced experimentally 
in the guinea pig. Ehrlich believes that at least two primary poisons 
are produced by the growth and multiplication of the diphtheria 
bacillus in nutrient broth; the one, toxin, produces acute death within 
about four days; the other, toxon, is incapable of causing acute death, 
but is responsible for the late palsies. In accordance with Ehrlich’s 
view, post-diphtheritic paralysis is a toxon poisoning. 
Ehrlich ^ has recently (1906) given a forcible defense of his clas- 
sical paper entitled ‘^The constituents of diphtheria toxin.” On ac- 
count of its importance in connection with our work, a brief sum- 
mary of Ehrlich’s views bearing upon diphtheritic paralysis or toxon 
poisoning is given practically in his own words, as follows: 
We are evidently dealing with a primary secretory product of the diphtheria bacilli, 
the “toxon.” 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. 
The presence of an independent poison (toxon) was inferred by Ehrlich from the 
curves shown in the spectra, which are based upon the assumption that 1 immunity 
unit contains 200 combining units. 
The independent existence of the toxons is further corroborated by the fact that the 
toxon zone varies enormously in different specimens of poison. In one it may amount 
to about one-fifth of the toxin portion; in another he has seen equal parts of toxon and 
toxin. Dreyer and Madsen in fact have recently described a poison which contained 
three times as much toxon as toxin. According to our present experiences, there- 
fore, the amount of toxon calculated on the toxin can vary from 0 per cent to 300 per 
cent. 
This still left undecided whether the toxon is a primary bacillary secretion or 
secondary modification of the toxin. A study of the development of one poison 
(poison V) finally gave Ehrlich a clue to this. (Poison V has been described in the 
Deut. med. Woch., 1898.) 
This particular toxine remained constant, as far as the L-fi close was concerned, 
but the L° dose increased considerably, from 0.125 to 0.21. Ehilich explains this 
phenomenon by assuming that the toxin portion remained absolutely unchanged, 
as indicated by the constancy of the L-f- dose. On the other hand, the toxon por- 
tion, which is expressed by the difference between the L-f and the dose, dis- 
appeared. This eliminates the possibility of the transformation of toxin into toxon. 
It is difficult to say, a priori, what becomes of the toxon which has disappeared. 
Ehrlich assumes that we are dealing with a formation of an analogue of toxoid, viz, 
a substance which he terms toxonoid. This he conceives to be a toxon in which the 
toxophore group has become modified. 
a Ehrlich, P.: Die WertbemessungdesDiphtherieheilserumsund derentheoretische 
Grundlagen. Klin. Jahrb., Jena, v. 6 (2), 1897, pp. 299-326. 
; Ueber die Constitution des Diphtheriegiftes. Deut. med. Woch., Leipzig, 
V. 24 (38), 1898, pp. 597-600. 
& Ehrlich, Paul: Studies on immunity. XXXVII, The constituents of diphtheria 
toxin. Xew AMrk, .lohn Wiley & Sons, 1906, p. 481. 
2748— Xo. 38—07 2 
