( 862 ) 
of the organism (of which the red corpuscles are for us the paradigm) 
against a toxic injection of the antigen. 
After the injection of the horse-serum directly into the circulation 
the serum of the sensitized guineapig shows just the reverse. In the 
above proportions with the other ingredients brought together to the 
conglutination-mixture it appears — compared with its action before 
the toxic injection — to further the fixation of the horse-alexine 
upon the guineapig-blood. Whence that sharp contrast *) in the results 
of the injections into the abdomen or into the circulation? The con- 
tradiction, however, is only a seeming and a relative one. For, it 
has further appeared to me that, if the last mentioned serum (viz. 
that of a sensitive animal after the second injection into the cireu- 
lation) is previously fcr some hours left in contact with the horse- 
serum before guineapig-blood and cattle-serum is added — the re- 
action in this mixture is then strongly retarded in comparison with 
another mixture, in which all these ingredients are directly added 
together without any previous mutual contact. It appears therefore 
that also in this serum after the intravascular injection there are 
still slumbering unneutralized antihorse-serum qualities, which can 
be brought to light only in the way just pointed out. 
The principal theoretical conclusion which I should like to draw 
from the above investigations is, that ir the (serum-)anaphylaxis we 
have to do with two contrasting principles: one is the basis of the 
hypersensibility, the other represents the immunity-principle, and 
both play a part in the mechanism of the anaphylactic complex of 
symptoms. 
Identification of blood-spots with the aid of anaphylaxis. 
Finally I am in a position to communicate here the foundations 
of a new method to distinguish the blood of man from that of 
animals and that of different kinds of animals from each other. 
I came to this or the ground of what follows. By former investi- 
gators it had been proved that with all kinds of sera a specific 
hypersensibility could be brought about: the same thing in general 
holds good for the most different proteins, among others also haemo- 
globin. Because moreover traces of these substances are sufficient, 
and also granted the fact that the sensitizing principle resists in- 
1) This does not seem so strange if it is borne in mind that from the abdomen 
the resorption takes place. gradually, whilst with injection into the carotis the 
circulation is suddenly overflowed by a relatively large quantity of the alien serum. 
Hence also the different reaction of the organism. 
