399 
Diphtheria Antitoxim. 
By JoHn ME.uansy, M.D., George Henry Lewes Student. 
(Communicated by Professor J. N. Langley, F.R.S. Received June 3,—Read 
June 25, 1908.) 
(From the Wellcome Physiological Research Laboratory and the Physiological Laboratory, 
Cambridge.) 
CONTENTS. 
MEMO RCA ees a Heyes oo was vn cieswiatsaisen cats Scie a oat neem ad. «Sudo tence eaaeeich dans vasswadeecss 399 
The Relation of Diphtheria Antitoxin to the Normal Proteins of Serum... 400 
The Relation between the Antitoxic Potency of a Serum and the Amount 
MME LEH Ic COMUALME UD Mite. e occa teecamatte cameecidne cede cceatwodstenteecrdeenecCiecccsis 408 
Penemunoory, Of Amtitoxin: PPOGUCHOM: .. 540.00. .s.cecvoceesscrsesentsenecorescsseeseenes 410 
pe HEINE Uterine ote ce Seine ate opts Seen GRA te AAO, Son aac hale ois cieis'w Gis Scie tnle nbieme deine «dee biel 412 
HISTORICAL. 
Many experimenters have endeavoured to isolate diphtheria antitoxin from 
fluids containing it. 
In 1893 Brieger and Ehrlich(1) investigated the properties of milk 
obtained from animals which had been immunised against diphtheria toxin. 
This milk contained an appreciable amount of antitoxin which could be 
precipitated between 27- and 38-per-cent. ammonium sulphate. By this 
method they were able to increase the antitoxic value of their fluid about 
five hundred times. But in milk only two proteins are present which differ 
widely in their physical properties—caseinogen and lact albumin—and their 
results could not be extended to horse serum, which is the main source of 
diphtheria antitoxin. Their experiments did not show that antitoxin is not a 
protein. 
Since horse serum is the main source of diphtheria antitoxin, experimental 
work has been done chiefly on this fluid. 
Aronson (2) stated that globulin precipitated from antitoxic serum by 
dialysis contained antitoxin. But Dieudonné showed that globulin precipitated 
by carbon dioxide from antitoxic serum did not possess this property. The 
protein precipitate obtained by both these workers corresponded to the 
globulin of serum as originally defined. Dieudonné further showed that if 
Hammarsten’s extended definition of globulin were adopted, then diphtheria 
antitoxin was a globulin, since it could be precipitated from serum by 
saturation with magnesium sulphate. 7 
