ADSORPTION BY SUSPENSIONS OF VARIOUS SUBSTANCES. 225 



volume of the venom solution, adsorbs most of the venom, probably as much 

 or only a little less than charcoal. Unlike charcoal, the aluminium oxide, when 

 injected into a living organism, gives off the venom. 



Kaolin does not adsorb venom as well as the three first-mentioned sub- 

 stances, and probably adsorbs but httle more than 70 per cent of the venom. 

 Like aluminium, kaolin holds the venom but loosely. 



Lecithin adsorbs considerable quantities of venom, but much less than 

 charcoal; its action appears to vary considerably; the addition of cholesterin to 

 the lecithin does not markedly alter the adsorption of venom. The venom 

 adsorbed by lecithin readily exerts its toxic action after subcutaneous injection 

 of the residue, due to the rapid absorption of the injected lecithin and the sub- 

 sequent dissociation of the venom-lecithin combination. 



The addition of dog or rabbit serum to the venom solution interferes very 

 markedly with the adsorption of venom by charcoal; the addition of a small 

 amount of alkali to the venom solution interferes considerably less than the addi- 

 tion of serum. Under the influence of alkali the venom-charcoal combination 

 is very much more easily dissociated in the body, alkali preventing the strong 

 fixation of the venom to the charcoal. 



In a similar manner an alkaline aluminium-oxide preparation adsorbs the 

 venom much less strongly than a neutral preparation. 



The addition of a small quantity of a weak acid to the venom solution 

 interferes only slightly with the adsorption of venom by charcoal. 



Olive oil adsorbs but little venom, and a considerable part of that adsorbed 

 is held by the very finest particles, as in the case of the venom adsorbed by 

 lecithin. 



If we turn to the adsorption of heloderma venom by suspensions of organs, 

 we can state in general that the pulp of organs adsorbs less venom than charcoal, 

 aluminium oxide, or carmine. The behavior of brain is very similar to emul- 

 sions of lecithin. In both cases the small particles that remain in the fluid after 

 centrifugation adsorb a certain quantity of venom. Even after filtration 

 through a Berkefeld filter these particles are not removed thoroughly and the 

 supernatant fluid retains a certain degree of toxicity. The whole brain adsorbs 

 less venom than emulsions of lecithin. That a certain amount of venom is 

 adsorbed by brain pulp is shown by the fact that the unfiltered is more toxic 

 than the filtered fluid, and, furthermore, by the toxicity of the residue which we 

 observed in certain cases. The fact that even after filtration the filtrate obtained 

 has not become harmless and that in a number of cases the mice injected 

 with the residue survived, shows that much of the venom remained unadsorbed. 



The brain of various species does not on the whole adsorb any more venom 

 than liver and kidney. This is clear in the case of guinea-pig. In no case did 

 the brain of any of the species tested adsorb as much venom as the liver and 

 kidney of heloderma and turtle. In this respect heloderma venom seems to 

 differ from cobra venom, which, according to Flexner and Noguchi, lost much 

 more of its toxicity after adsorption by brain than by other organs. Also, 

 Calmette and Eogers found that brain adsorbs much snake venom. 



