ANTITOXINS 111 



In favor of tho view that antitoxin is a definite protein body is 

 also the fact that it is not carried down in indifferent precipitates, as 

 are the enzymes, but conies down always in a certain fraction of the 

 protein precipitates, e. g., we can precipitate all the serum albumin 

 from an antitoxic serum, and it does not carry down with it any of 

 the antitoxin. Another important point has been brought out by 

 Ai-rhenius and IMadsen,^''' who determined approximate^^ the molecu- 

 lar weight of toxin and antitoxin by means of their rate of diffu- 

 sion, and found that the toxin (diphtheria toxin and tetanolysin) 

 diffused ten or more times as rapidh' as the corresponding antitoxin. 

 Gelatin filters also hold back antitoxin and let toxin pass through, 

 and toxins diffuse into cells which seem to be impermeable for the anti- 

 toxin. This indicates that the antitoxin molecules are much larger 

 than the toxin molecules, agreeing with the idea that antitoxin is of 

 protein nature and that toxin either is not protein or is smaller than 

 most protein molecules. 



Taken altogether, the evidence indicates a closer resemblance of 

 antitoxins to proteins than has been show^n for the toxins, and all 

 attempts to separate antitoxins from proteins have so far failed. 



Antitoxins are retained to greater or less extent by porcelain 

 filters, do not pass through dialyzing membranes readily, and are in 

 general easily destroyed by chemical and physical agencies, although 

 much less so than are most toxins. Heating to 60°-70° injures, and 

 boiling quickly destroys them, although like the enzymes and the pro- 

 teins, they resist dry heat to 140°, and also extremely low temperature, 

 without change. Putrefaction of the serum destroys the antitoxins 

 (Brieger)." They can- be preserved for a very long time when dried 

 completely, but in the serum they gradually disappear, especially if 

 exposed to light and au*. Acids and alkahes destroy antitoxins, 

 acids being the more harmful in low concentrations. Like the enzymes, 

 antitoxins are destroyed hj ultra-violet ra3-s. They are destroyed in 

 the alimentar}' tract, without appreciable absorption, except in the 

 case of new-born animals sucking mothers whose blood and milk 

 contain antitoxin. ^^ When subcutaneousl}'- injected, antitoxin soon 

 disappears from the blood; part may be bound to the tissues, part may 

 be destroyed, since only traces appear in the urine. It resists 

 autolysis. ^^ 



" Festskrift Statens Serum Institut, 1902. 



" Behring states that tetanus antitoxin resists putrefaction. 



98 Romer and Much, Jahrb. f. Kinderheilk., 1906 (63), 684; McCIintock and 

 King (Jour. Infect. Dis., 1906 (3), 701) found appreciable absorption of antitoxin 

 when digestion was impaired bj^ drugs. Full review of literature on transmission 

 of antibodies from mother to offspring given bv Famulener, Jour. Infect. Dis., 

 1912 (10), 332; Heurlin, Arch. Mens. Obs. et Gvn., 1912 (1), 497. 



" Wolff-Eisner and Rosenbaum, Berl. klin. Woch., 1906 (43), 945. 



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