K. LANDSTEINER 895 



agglutinogens A and B but by the presence of a particular agglutinogen for which no 

 agglutinin exists in normal human sera (see p. 902). (If Schiff's agglutinable factor 

 corresponds to Bernstein's genetic R, one might expect that his observation would 

 lead to a serological differentiation of individuals homozygous or heterozygous as to 

 the agglutinogen A or B.) 



Aside from the red corpuscles, group specific substances were found by special 

 procedures in sperm cells, seminal fluid, saliva, and in organ tissues and the blood 

 serum.' In blood platelets isoagglutinogens could not be demonstrated.^ Isoaggluti- 

 nins are also present in milk,^ 



ISOHEMOLYSINS 



On mixing fresh human serum, which contains complement, with the erythrocytes 

 of other individuals, hemolysis — isohemolysis — can also occur, occasionally masking 

 the agglutination. This isolysis was regarded by some early authors, like isoagglu- 

 tination, as a pathological phenomenon, but it was shown that it likewise depends 

 on the constitutional group qualities.'' That is, isolysis occurs only along with 

 isoagglutination, but the incidence of isolysis is much rarer with the usual technique. 

 By modifying the method, namely, taking large amounts of serum^ or making the 

 cells more susceptible by storing the washed corpuscles for several days,'' the fre- 

 quency of hemolysis can be increased considerably so as to approximate the incidence 

 of isoagglutination. In certain pathological cases the titre of isolysis was found to be 

 higher than usual. 



Group-specific complement-fixing antibodies in a few normal human sera and also 

 opsonins were described by Schifi and Adelsberger,^ antilytic substances by Moss, 

 Jervell,^ and others. 



DEVELOPMENT OF THE ISOAGGLUTINATION ELEMENTS 

 QUANTITATIVE VARIATIONS 



In newborn children the isoagglutinins are often missing or present in small 

 amounts only. In part they are derived from the mother, but agglutinins have been 

 found in infants, that are not present in the mother's serum (von Decastello and Sturli, 



I Yamakami, K.: /. Immunol., 12, 185. 1926; Landsteiner, K., and Levine, P.: ibid., p. 415. 

 1926; Ashby, W.: Am. Ass. Immunol., May 4, 1925; Witebsky, E.: Ztschr. f. Immimitatsforsch. u. 

 exper. Therap., 49, 517. 1927; Schiff, F.: Klin. Wchnschr., 3, 679. 1924; Kritchewski, I. L., and 

 Schwartzmann, L. A.: Klin. Wchnschr., 6, 2081. 1927; Ouchi, I.: Ztschr. f. Immunitatsforsch. 11. exper. 

 Therap., 53, 462. 1927. 



^Toda, T.: /. Path. &" Bad., 26, 303. 1923. 



3 Landsteiner, K.: Wien. klin. Rundschau, No. 40. 1902. Cf. Happ, W. M.: /. Exper. Med., 31, 

 313. 1920. 



''Landsteiner, K., and Leiner, K.: Centralbl. f. Bakteriol., 38, 548. 1905; Grafe, E., and Gra- 

 ham, D. A. L.: Miinchen. med. Wchnschr., 2257, 2338. 1911. 



5 Williams, W. C.: /. Exper. Med., 32, 159. 1920; Jones, B. B.: Am. J. Dis. Child., 22, 586, 598. 

 1921. 



*Hesser, S.: Akt. med. Skand. Suppl., 9, i. 1924. 



7 Schiff, F., and Adelsberger, L.: Centralbl. f. Bakteriol., 93, 172. 1924; Ztschr. f. Immiinitats 

 forsch. u. exper. Therap., 40, 335. 1924; Schiff, F.: Med. Klin., 21, 1238. 1925. 



* Jervell, F.: Mitt. d. Grenzgeb. d. Med. u. Chir., 34, 650. 1922. 



