14 



Scientific Proceedings (25). 



6 (262) 



The role of tonicity in human isohemagglutination. 



By FREDERICK P. GAY. 



[From the Laboratory of the Danvers Insane Hospital, 

 Hatlwrne, Mass.] 



As was shown by Landsteiner and others, human bloods fall 

 into three rather definite groups as regards isohemagglutination. 

 The serum of members of group I agglutinate the corpuscles of 

 groups II and III, but the corpuscles of group I are not agglu- 

 tinated by any foreign human serum ; members of group II agglu- 

 tinate group III and are agglutinated by them ; serum of members 

 of group III agglutinate corpuscles of group II. Individuals in 

 groups II and III, respectively, do not interagglutinate. It was 

 found that constant relative differences in tonicity were present 

 between these isoagglutinating groups, as was determined by the 

 varying resistance, to hypotonic salt solutions, by the corpuscles 

 of members of the respective groups, and by testing the tonicity of 

 the various corresponding sera. Thus the tonicity of bloods of 

 group I is found uniformly higher than that of bloods of groups 

 II and III ; bloods belonging to group II are higher in tonicity 

 than those of group III. Simple hypertonic solutions of CaQ 2 , 

 but more particularly solutions hypertonic both in respect to NaCl 

 and CaCl 2 , produce a cohesion of human blood after several hours, 

 that suggests isohemagglutination. 



It is evident that hypertonicity alone, as regards total molecular 

 concentration of all the substances present in serum, cannot ac- 

 count entirely for human isohemagglutination ; although group II 

 sera would agglutinate group III corpuscles, group III sera could 

 not agglutinate group II corpuscles, as is the case. Relative dif- 

 ferences in concentration of one or several salts or colloids could 

 account for all the phenomena, as a given blood might be of higher 

 molecular concentration in respect, say, to CaCl 2 , and yet in total 

 concentration be inferior to another blood, which it agglutinates. 



It may be shown that when a serum of group I agglutinates a 

 member of group II, and another of group III, the agglutinating 

 power is apparently specific for each, as may be proved not only 



