1168 
In the following table the degree of hemolysis after one bour is 
indicated as follows: 
ce = complete; a.c. = almost complete; m — marked; d = distinct; 
f= taint; dr = rangs n= none; 
Injection of 
preparation I {I | Ill | IV Vv 
Number of Ae, oa SAT) DS) EE | | | 
| | | | IK | | 
the rabbits I | 2 | 3 | 4 | 7 | 8 9 me a il ss pe be 21 Pee a 
BR 14) KE Pi abs, ie Ua: Wk, 
c. jc ew Coke ob. | o. | d. kid | m. 0. | 0. (tr. | tr. ac. C. | c ls 
| PSE Se PERU | | | ú 
Sera 1, 2 and 4 also dissolved completely in dilutions of 1 : 1000, 
1:500, 1:500. The experiment described here, indicate that the 
kidney-substance, treated with alcohol at room temperature, has still 
the power to generate hemolysins but in a much smaller degree than 
the original emulsion. Under the actual conditions this immunizing 
capacity was abolished almost completely by boiling with alcohol. 
The antigenic property is still well preserved after boiling in aqueous 
solution (Dorrr and Pick), although it should be noted that the 
serum titre was lower than after the injection of the unheated 
material. : 
My investigation therefore proved that by treating with alcohol, 
substances are brought into solution, which react with hemolysin in 
vitro; that however, they have lost their immunizing capacity, and 
that the residue which is left after aleohol-extraction, has a much 
weaker antigenic property, which is all but abolished after heating 
with alcohol. 
It seems to me that the most obvious interpretation of the facts 
recorded is, that the antigen is made up of a part, that is essential 
to immunization and is probably built up of protein, and of anotber 
part combined with this, which contains the specific reacting groups 
and is perhaps a lipoid. Furthermore it appears, that the latter can 
be separated from the former by means of alcohol. 
This view is supported chiefly by results obtained in experiments 
that I published some time ago’). These experiments proved that 
there are substances which probably react specifically in vitro, without 
being antigens. 
As it will be convenient to have a special name for such 
1) K. LANDSTEINER. Biochem. Zeitschr. 93. pag. 106 (1919) Biochem. Zeitschr. 
104. pag. 280 (1920). 
