Physiology. — ‘On Heterogenetic Antigen”. By K. LANDSTEINER. 
(Communicated by Prof. C. H. H. Spronck). 
(Communicated at the meeting of lebruary 26, 1921). 
It is well known that Forssman ') discovered the fact, that by injection 
of organs of guinea pigs into the rabbit the formation takes place 
of a strongly active specific hemolysin against sheep’s blood. It soon 
was observed that the same property may be ascribed to the organs 
of a large number of animals, e.g. to those of the horse, the cat 
and the fowl, whereas these active substances are absent in other 
animal species. 
These substances are generally called heterogenetic antigens; the 
hemolysins generated by their injection are termed heterogenetic 
antibodies. 
A complete account of the investigations on this subject and their 
results will be found in the publications referred to below. In this 
paper I shall record only the results regarding the heterogenetic 
antigen which are of special interest for my work. 
Doerr and Pick?) found that the said substances of the organs 
are resistant to the influence of alcohol; Sachs and Grorer’) record 
the use of alcoholic extracts, FRIEDBERGER *) (Poor, Suro, SCHIFF) report 
the solubility in alcohol of the heterogenetic antigen occurring in 
the urine (see Dorrr and Pick) of animals. SorDELL and Frscaer ®) 
found that the active constituents of the horse’s kidney can be split 
into two fractions by treating with alcohol (and ether), the one of 
which fractions, soluble in alcohol, combines in vitro with immune 
bodies, but does not bring about immunization, while the part 
that is insoluble in alcohol and ether, combines only inappreciably 
in vitro; however, 7 generates immune bodies. (SorDELLI and 
Pico®) also observed, just as Sacus and GutH’) did, a flocculation 
1) J. ForssMan. Biochem. Zeitschr. 3%. pag. 78 (1911). 
4) R. Doerr en R. Pick. Biochem. Zeitschr. 50. pag. 129 (1918). : 
3) SacHs en GEORG. Zeitschr. f. Immun. 21. pag. 346 (1914). 
4) FRIEDBERGER. Berl. Klin. Wochenschr. 1913, N. 34. Zeitschr. f. Immun. 18 
pag. 269 (1913) 28. pag. 217 (1919). 
6) SORDELLI en FiscHeER. Revista del Inst. Bacteriol. Buenos-Aires. Vol. I. 1918 
pag. 229. 
6) SoRDELLI en Pico. Revista del Inst. Bacteriol. Buenos-Aires Vol. I. 1919. p. 261. 
7) SacHs en GurH. Mediz. Klinik 1920 No. 6. 
