( G24 Ye 
from the serum the substance that is toxic for sensitive animals. *) 
This procedure was already for another reason known in the 
immunity-literature, because in this way also the alexine from the 
horse-serum is fixed upon the blood of the guinea-pig. *) 
Serum treated thus has for anaphylactic animals lost its poisonousness, 
and this fact seems to me to open a new point of view. For it 
proves that there exists affinity between the toxic principle of horse- 
serum and cellular elements already of the normal pig-organism. 
The supposition does not seem to be too bold that also other elements 
of tissue or organs of the guinea-pig are subjectable to such a fixation, 
and that this affinity is still enhanced in the anaphylactized animal. 
The reaction between the horse-serum and the sensitive elements — 
especially those of the central nervous system — would then give 
rise to the action of the anaphylactic shock, whilst by the side of 
this the secondary fixation of the alexine would be the consequence 
of this reaction to be observed in the serum. Starting from these 
facts and considerations I continue my investigation in this direction. 
In the meantime it is worth while to point out here that already 
some time ago v. BEHRING drew the attention to the paradoxical fact 
that a horse containing abundant diphtheria-antitoxines in its blood, 
can yet react upon a relatively small dose of toxine with symptoms 
of poisoning and even with death. Therefore v. Benrinc presumed 
the existence of an Aistogenetic hypersensibility, which hypothesis, in 
connection with what precedes, grows more probable. 
To the many attemps made by different investigators with varying 
results, to deprive horse-serum of its toxicity by the help of physical 
or chemical means, I have tried to add another, which had a satis- 
factory result. | have namely submitted to dialysis horse-serum in 
so-called “Fischblasencondome”. From this it appeared that the arising 
precipitation, dissolved in a physiological salt-solution, shows no 
trace of toxicity with respect to sensitized guinea-pigs, whilst the 
serum floating on the surface and free from salt (before the animal- - 
experiment reduced to isotonical proportions), gradually loses its 
poisonousness during the process of dialysis. 
Now the proof for the non-poisonousness just of the filtrate is not 
devoid of importance, because former investigations have shown that 
in dialysing antitoxical horse-serum the diphtheria-antitoxines (which 
1) Take for 1 vol. serum: 11/3 vol. blood and 2 vol. salt solution. — On simple 
dilution with salt-solution in the same proportions, the serum retains its toxicity. 
2) See about the meaning of this phenomenon: Ehrlich and Sachs, Berl. Klin. 
Woch. 1902, no. 21 and Bordet and Gay, Annales Pasteur 1906. 
