ISO AGGLUTINATION ELEMENTS 



467 



In the course of a class demonstration of the two original 

 pairs of isoagglutination elements, the serum of one of us (A. F. 

 C, a Group I individual) was absorbed, first with the washed 

 corpuscles of a Group II individual (Levine) and then with the 

 washed corpuscles of a Group III individual (Sutton). The 

 supernatant fluid, after these absorptions, no longer clumped the 

 corpuscles of the respective Group II and Group III individuals, 

 but still possessed a vigorous power of agglutinating the cor- 

 puscles of a Group IV individual (Johnson) which were agglu- 

 tinable by the serum of both Levine and Sutton. 



This observation indicated the presence of another unde- 

 scribed pair of isoagglutination elements, which we shall tenta- 

 tively designate as x (isoagglutinin) and X (isoagglutinable sub- 

 stance). 



Examination of 10 other Group I sera revealed the presence 

 of "x" in 7 of them (see Table II). 



It is evident that the agglutinable substance "X" is lacking in 

 the Group II and Group III corpuscles that were used for the 

 absorption. Six other Group III corpuscles have been exam- 

 ined and all were found to lack the agglutinable substance "X." 

 Of 13 other Group II corpuscles only 2 have been found to lack 

 this substance. 



No other Group IV corpuscles have been available. 



Six Group III sera have been examined and of these, 2 have 

 been found to possess the isoagglutinin "x;" the other 4 

 lacked it. 



TABLE II. 



After absorption with 

 Group Unabsorbed L and S corpuscles 



I tested with corpuscles of tested with corpuscles of 





Sera. 



L 



S 



L 



s 



J 



1 



(A.F.C.) 



+ + 



4- 4- 



0 



0 



4- 4- 



2 



+ + + 



4- 4- 



0 



0 



+ 4- 



3 





4- + 



+ + 



0 







4 





4- + 



+ + 



0 



0 



0 



5 





4- 4- 



4- + 



0 



0 



4- 4- 



6 





+ 



+ 



0 



0 



4- 4- 



7 





+ + 



+ + 



0 



0 



+ + 



8 





+ + 



4- + 



0 



0 



4- + 



9 





4- + 



* 4- 



0 



0 



4- 4- 



10 





+ + 



4- + 



0 



0 



0 



11 





4- + 



4- + 



0 



0 



0 



L — P. Levine (Group II lacking agglutinable X). 

 S = H. B. Sutton (Group III). 

 J = S. Johnson (Group IV). 

 + = agglutination. 



