The Antagonism between Toxins and Antitoxins. 423 



the product of the active masses of the reacting bodies present. 

 Temperature will also exercise an important influence. 



As we shall later show, the experiments quoted by these observers 

 can easily be repeated and the same results obtained. Nevertheless 

 their conclusions are quite unjustified, and by modification of the 

 factors, time, temperature, and active masses, exactly opposite results 

 may also be obtained. 



Experimental results obtained by the Authors. 



Our experiments have been conducted with the toxin of diphtheria, 

 and one of the constituents of the poison of the Australian tiger 

 snake (SoplocepTialus curtus.) 



The diphtheria toxin was prepared by cultivating the organisms 

 in broth made from well hung beef, after the method of Spronck.* 

 It was filtered through a sound Pasteur-Chamberland filter, and the 

 toxin strength of the filtrate determined by injection into a series 

 of guinea-pigs. That with which most of our experiments were 

 conducted, had a minimum lethal dose of 0'12 c.c. per kilogram in 

 48 hours. 



The antitoxins used were Behring's No. 1 and serum from the 

 Pasteur Institute, Paris. 



The constituent of the venom used was the one which is not 

 destroyed by heating a solution of venom to 90 C. This consti- 

 tuent resembles most closely, if indeed it be not identical with, the 

 principal constituent of cobra poison ; and, as shown by one of us,f 

 Calmette's antivenomous serum possesses a small but decided counter- 

 acting action upon it. This action, though unfortunately of little or 

 no practical importance, is sufficient for our present purpose, for in 

 our experiments we could mix comparatively large quantities of the 

 serum with small fatal doses of the venom in vitro. Under these 

 circumstances one could easily neutralise the poison. 



The antitoxin was the antivenomous serum prepared by the Pasteur 

 Institute at Lille, and bore date November, 1896. 



We endeavoured at the outset to determine whether the action of 

 antitoxins upon toxins were chemical or physiological, by a direct 

 physical method. In 1896 one of usj published an account of a 

 method of separating substances of large molecular size from those of 

 smaller, in solutions containing both. This method was simply by 

 filtering through a film of gelatin, supported in the wall of a 

 Pasteur-Chamberland filter. The filtration was accomplished by a 

 pressure of 50 atmospheres. 



* ' Ann. de 1'Inst. Pasteur,' 1895. 



f C. J. M., ' Intercolonial Med. Journ. of Australasia,' August, 1897. 



J C. J. M., < Journal of Physiol.,' rol. 20, 1896. 



