NEUTRALISATION OF SIMPLE POISONS 215 



for 3 hours at 37 C. and thereafter the fluid separated 

 from the erythrocytes by centrifugalisation and its content 

 of cobra-poison determined. As is so common, no indica- 

 tion is given of the magnitude of the experimental error, 

 which we may estimate as very low, 5 per cent. Morgen- 

 roth found that " absolutely " (!) no cobra-poison had been 

 absorbed by the erythrocytes. The correct conclusion 

 would evidently have been that less than 5 per cent of the 

 poison was removed. A calculation from the figures given 

 above (K =0.00 1 4) shows that about o.i per cent of the 

 poison was free in the liquid. If now the erythrocytes 

 had absorbed ten times this quantity, it would have been 

 five times less than the least quantity which Morgenroth 

 would have been able to detect. Perhaps the erythrocytes 

 absorbed even the antitoxin in this case. 



It is to be regretted that Morgenroth has chosen this 

 particular compound to determine whether a partial dis- 

 sociation occurs, since it was well known from Kyes' ex- 

 periments that it is dissociated to an extremely low degree 

 (Kyes asserted that it was not dissociated at all) ; and also 

 that Morgenroth used such a large excess of antitoxin to 

 still more suppress the insignificant degree of dissociation. 

 Morgenroth might well have used much more dissociated 

 compounds in his experiments without still being able to 

 detect the dissociation-products with the means employed 

 by him in this case. 



Biltz 1 has investigated the neutralisation of arsenious 

 acid (As 2 O 3 ) by means of "freshly precipitated ferric 

 hydrate." This hydrate has a physical constitution like 

 that of gel, and behaves just as a colloid in its absorption 



1 Biltz: Ber. d. deutschen chem. Ges. 37. 3138 (1904). 



