898 THE HUMAN BLOOD GROUPS 



to agglomerate the erythrocytes of the same or other individuals in the form of 

 rouleaux, or clumps resembling those produced by true agglutination (Shattock).' 

 The phenomenon is also very marked with normal horse blood. 



As was shown by Shattock, this form of clumping — pseudoagglutination — dis- 

 appears on slight dilution (1-2 or 1-3) of the serum, and can therefore be distinguished 

 readily from isoagglutination. By treating the serum with red cells the active princi- 

 ple is not absorbed in contradistinction to agglutinins.^ A phenomenon very similar 

 to pseudoagglutination is brought about when certain colloidal substances such as 

 gum arable or gelatin are added to blood suspensions. 



AUTOAGGLUTINATION^ 



When animal or human erythrocytes are mixed with a sufficient quantity of serum 

 of the same individual and kept at low temperature (icebox) the cells mostly settle 

 in clumps after some time. The reaction is diminished by an increase in temperature, 

 and, as a rule, disappears entirely at 37° C. The active principle is absorbed by the 

 cells in the cold and set free by slight warming. When, therefore, the agglutinated 

 cells are washed with ice-cold saline and are resuspended in saline at room tempera- 

 ture, the clumps break up, and after centrifuging the supernatant fluid contains the 

 agglutinin. Its presence can be demonstrated by adding blood cells to the fluid and 

 chilling the mixture. The determining effect of temperature, and also the absorption 

 of the active substances by the cells, distinguishes autoagglutination from pseudo- 

 agglutination. The speed of sedimentation due to pseudoagglutination is ordinarily 

 not lower and, indeed, may be higher at 37° C. than at room temperature; it is not de- 

 pendent on the content of autoagglutinins in the serum. A high degree of autoagglu- 

 tination has been observed in certain pathological conditions as in syphilitic or h}'per- 

 trophic cirrhosis, paroxysmal hemoglobinuria, Raynaud's disease, hemolytic icterus, 

 anemia, spirillosis, and trypanosomiasis of man and animals. In rabbits the forma- 

 tion of powerful agglutinins could be induced by repeated transfusions with rabbit 

 blood or repeated bleedings.^ The occurrence of abnormal agglutinins acting on bloods 

 of all groups and due to bacterial products was described by Lacy.^ 



Agglutination reactions produced by sera of any group were described by Hii- 

 bener, Schiff and Halberstaedter,'' and Thomsen,^ with blood samples kept for one or 

 several days. In Thomsen's case the agglutinability could be transmitted to other 

 blood specimens by adding some of the peculiar blood, and it was found that the 



' Shattock, S. G.: J . Path, b' Bad., 6, 303. 1900; a detailed study was made by Wiltshire, H.: 

 ihld., 17, 282. 1913. 



2 Meyer, K., and Ziskoven, H.: Med. Klin., 19, 87. 1923. 



i Landsteiner, K.: Miinchen. med. Wchnschr., 50, 1818. 1903; Mino, P.: Deutsche med. Wchnschr., 

 50, 1533. 1924; Alexander, H. L., and Thompson, L. D.: J.A.M.A., 85, 707. 1925. 



1 Rous, P., and Robertson, O. H.: /. Ex per. Med., 27, 509, 503. 1918. 



5 Lacy, G. R.: /. Immunol., 14, 189. 1927; cf. Eisenberg, P.: Centralbl. f. BakterioL, 34, 739. 

 1903. 



^' Schiff, F., and Halberstacdter, W.: Ztschr.f. Immnnitdtsforscti. it. e.vper. Tlierap., 48, 414. 1926 



' Thomsen, O.: Soc. Biol., 96, 556. 1927, cf. p. 1079; Ztschr.f. Immunildtsforsch. u. e.vper. 

 Tlicrap., 52, 85. 1927; Friedenreich, V.: Soc. Biol., 96, 1079. ig_'7; 97, 1266. 1927. 



