1 8 IMMUNE SERA 



acid. In general they withstand a fair degree of 

 heat, certainly far more than the toxins. Anti- 

 toxins are to be regarded as inactive substances, 

 effecting merely a blocking of the haptophore 

 group of the corresponding toxin. They do not 

 act on the toxins destructively. This is indicated 

 by experiments of Wassermann on pyocyaneus toxin, 

 and of Calmette and Morgenroth 1 on snake venom, 

 which showed that in the toxin-antitoxin com- 

 bination, the toxin could again manifest itself after 

 the antitoxin had been destroyed. The antitoxins 

 therefore are not ferment-like substances. As far 

 back as 1897 attempts were made to determine the 

 chemical nature of the antitoxins. In that year 

 Belfanti and Carbone 2 found that the antitoxin 

 was precipitated with the globulins of the serum by 

 means of magnesium sulphate. Dieudonne 3 had 

 previously shown that the proteids thrown out of 

 solution by acetic and carbonic acids contained 

 none of the antitoxin. In 1901 Atkinson 4 showed 

 that the globulins increase markedly in the serum 

 of horses as the antitoxic strength increases. The 

 most recent work on this subject is that of Gibson, 5 

 who shows that if the ammonium sulphate precipi- 



1 Morgenroth, Berlin, klin. Wochenschr. 1905. 



2 Beifanti and Carbone, Centralblatt Bacteriologie (Ref.), 

 Vol. xxiii, 1898. 



3 Dieudonne, Arbeiten a.d. kaiserl. Gesundheitsamte. VoL 

 xiii, 1897. 



4 Atkinson, Jour. Exper. Medicine, Vol. i, 1901. 



5 Gibson, Journ. Biological Chemistry, Vol. i, 1906. 



