(160°) 
entirely freed from it. Both the extract and the residue are now, 
each in their turn, treated with 5 eM? of physiological salt-solution 
and thus reduced to the original volume. The extract yields an homo- 
geneous fatty emulsion; the residue with the water forms into a 
thick liquid, jelly-like mass’). Now the first is quite indifferent to 
sensible guinea pigs; not only is it absolutely unpoisonous, but the 
animals remain also after the injection of it as sensible to an injection 
of fresh serum as before. Meantime the part of the serum not soluble 
in aleohol, wholly injected into sensitized animals, does not give, or 
hardly gives, rise to symptoms of poisoning, but vaccinates against 
a later, in itself toxical, injection with normal serum. For this vacci- 
nation, however, very small doses of the residue, as Brsrepka found 
them sufficient for intact serum, do not suffice. Therefore the active 
part of the serum has, through the action of the alcohol, lost together 
with its toxicity also a part of its vaccinating power. At any rate 
the proteine-nature of the antigen of anaphylaxis seems in my opinion 
to be well proved by what is said above. 
In continuation of the methods explained in my former commu- 
nication to eliminate the toxical principle of horse-serum for sensitized 
guinea pigs (fixation upon pig-blood, dialysis), I am now able to add 
to them a third process. It is based upon recent and very important 
investigations of GeNaou*). The latter proved among others, that, 
while water possesses no capacity of suspension for bariumsulphate, 
in consequence of which this powder rapidly subsides, this sedimen- 
tation changes into a dissemination in the presence of some stable 
colloids. This dissemination is based upon a molecular adhesion, a 
real adsorption of the colloid by the powder. To the colloidal solu- 
tions that show this quality, belongs among others the serum. From 
an oral communication of GENGou which has not yet been published 
it further appeared to me that this investigator had succeeded, by 
contact of fresh serum with BaSO, in salt-solution, in depriving this 
serum of its alexine. This led me to try if perhaps also the toxical 
principle of horse-serum would be absorbed by this powder. It really 
appeared to be the case. For this purpose is used a suspension of 
bariumsulphate in physiological salt-solution containing about 70 m.gr. 
BaSO, per 1 cM’. Three parts of this (or the sediment of it) are 
treated with 1 part: of serum. If, however, instead of physiological salt- 
solution, distilled water is taken as vehicle for bariumsulphate — or 
the dry powder, when there is no salt-solution — then the serum 
1) Neither is able to fix alexine in vitro, in the presence of anaphylactic pig serum. 
o 
2) “Contribution à l'étude de l’adhésion moléculaire et de son intervention dans 
divers phénomènes biologiques.” Arch. internat. de Physiol. 1908, Vol. VII, 
