Physiology. — “On the serological specificity of haemoglobin in 
different species of animals”. By K. LANDSTEINER. (Communi- 
cated by Prof. C. H. H. Spronck). 
(Communicated at the meeting of January 29, 1921). 
The knowledge of species-specificity is based principally on morpho- 
logical facts, on the phenomena of inheritance and transplantation, 
and on serological reactions. The first allow the direct inference 
that species-specificity is a property of all the constituents of the 
body; serological data, on the other hand — as far as animal 
organisms are concerned — bear first of all on the proteins of the 
blood serum. 
Concerning these latter there exist numerous results of precipitin 
tests, of which the greater part were carried out by Nurrats’), 
and which may be summarised, that serological relationship in 
general corresponds to the zoological classification and that the diffe- 
rence of the precipitin reactions increase in a measure corresponding 
to the difference in the scale of animal classification. 
For the other constituents of the body an analogous relationship 
is probable, and is often accepted as a matter of fact; this subject, 
however has been far less thoroughly investigated than the properties 
of the bloodserum. 
Some proteins differ in a greater degree (protein of the eye-lens®) 
and the horny substance*)) and others (casein®)) in a smaller 
degree from the specificity type mentioned i.e. their specificity is 
more or less independant of the animal species. In these cases we 
cannot exclude the possibility that the species-specificie structure 
although present is concealed by other structures. 
Whether the haemagglutinating immune-sera with regard to their 
group reactions correspond as well to the zoological classification, 
as the before mentioned precipitins, is indeed still doubtful °). 
1) NurrarL. Bloodimmunity and bloodrelationship, Cambridge (1904). 
2) UHLENHUTH. Festschr. f. Rob. Koch. 
8) Krusius. Arch. f. Augenheilk. 67. (1910). 
4) VersELL. Zeitschr. f. Immunitätsf. 24. 267. (1915). 
5) Cf. Lanpstemer u. Reien. Zeitschr. f. Hyg. 58. 227. (1907). 
BROCKMANN. Zeitschr. f. lmmunitätsf. 9. 114 (1911). 
75 
Proceedings Royal Acad. Amsterdam. Vol. XXIII. 
