1911] on riiysical diemis^irii and the Doririno of hniiuinity. -I'lU 



Danysz, a Polish scientist in the Pastenr Institute in Paris, ob- 

 served a peculiar phcnoTnenon — which has been called, after him, tiie 

 Danysz-effect — in the neutralization of ricin or diphtheria poison by 

 their specific antitoxins. He divided the poison in two parts, ;ind in 

 one experiment he mixed a given quantity of antitoxin with both 

 parts simultaneously ; in another experiment he added only the one 

 part of the poison to the same quantity of antitoxin, and after some 

 hours (at ;!7^ C.) be added the second part of the poison. After the 

 poison had had sufficient time to react with the antitoxin, the two 

 mixtures w^ere investigated, and it was found that the second inixture 

 was more poisonous than the first. A similar effect was found later 

 on with tetanolysin, staphylolysin, and rennet. 



This effect seemed very peculiar ; it was, therefore, used by the 

 opponents against the chemical theory of the binding of toxin through 

 antitoxin as an objection against this theory, notwithstanding that 

 they were unable themselves to explain the phenomenon otherwise 

 than by supposing the occurrence in the poisons of some new hypo- 

 thetical substances, called epitoxonoids Madsen and Walbum 

 therefore carried out a very great number of experiments regarding 

 the Danysz-effect in regard to tetanolysin, which I treated theoretically 

 afterwards. I found that the Danysz-effect corresponds to the fol- 

 lowing well-known chemical process. 



Suppose we replace the poison with monochloracetic acid, 

 CH2CICOOH, and the antitoxin by an equivalent quantity of caustic 

 soda. If I mix the whole quantity of the acid with the alkali, I get 

 a neutral solution of sodium-monochloracetate, which remains neutral 

 for a long time even at a high temperature (65° C). 



If I in anotlier experiment divide the acid in two equal parts, and 

 mix only the one with the said quantity of caustic soda, at 65° C, 

 then a neutralization immediately takes place, and there remains a half 

 equivalent of alkali in presence of a half equivalent of sodiummono- 

 chloracetate. These two substances give rise to a slow reaction, 

 by which sodium-chloride and sodium-glycolate are formed — 



NaOH + NaCH^ClCO^ = NaCl + NaCH^OHCO, 

 and at the end of this reaction the solution is neutral. If I now add 

 the second half equivalent of the monochloracetic acid, the mixture 

 has a strongly acid reaction, whereas if the two half equivalents of 

 acid had been added to the equivalent of caustic soda, the solution 

 would not have been acid at all. 



This phenomenon corresponds wholly to the Danysz-effect. It is 

 evident that no effect would have been found if the (piantity of alkali 

 present in the first instance had not exceeded the quantity of acid 

 added — i.e. an excess of alkali is necessary, and the effect is j)ro- 

 portional to this excess. Quite the same holds good for the Danysz- 

 effect, as I found by calculation. The experiments had been 

 performed so that 1 c.c. of tetanus poison (a highly diluted prepara- 



YOL. XX. (No. 105) Q 



