HEMAGGLUTININS 287 



serum, whereas the serums agglutinate the corpuscles of the other groups. 

 This group includes about 50 per cent, of all persons. 



Group 2 : In this group the corpuscles are agglutinated by the serums 

 of groups 1 and 3 only, whereas the serums agglutinate the corpuscles of 

 groups 3 and 4, but not of Group 1. 



Group 3: The corpuscles are agglutinated by all other serums, and 

 the serums agglutinate the corpuscles of groups 2 and 4, but not of 

 Group 1. 



Group 4: The corpuscles are agglutinated by the sera of all other 

 groups, but the serums are unable to agglutinate any human corpuscles. 

 These are quite rare. 



The group characteristics are hereditary, and permanent throughout 

 life. 



Moss found that all normal and pathologic bloods alike could be 

 classified into four groups by agglutination tests of the serums against 

 the corpuscles. These groups are: 



Group 1 (10 per cent.) : Serum does not agglutinate any corpuscles. 

 Corpuscles agglutinated by the serums of groups 2, 3, and 4. 



Group 2 (40 per cent.): Serum agglutinates corpuscles of groups 

 1 and 3, not 2 or 4. Corpuscles agglutinated by serums of groups 3 and 4, 

 not 1 or 2. 



Group 3 (7 per cent.) : Serum agglutinates corpuscles of groups 



1 and 2, not 3 or 4. Corpuscles agglutinated by serums of groups 



2 and 4, not 1 or 3. 



Group 4 (43 per cent.): Serum agglutinates corpuscles of groups 

 1, 2, and 3, not 4. Corpuscles not agglutinated by any serums. 



It may be seen that no serum agglutinates corpuscles belonging 

 to its own group, and furthermore, that if one has a known Group 2 or 

 Group 3 blood, he can determine the group of any other blood by testing 

 the known serum against the unknown corpuscles, and the unknown 

 serum against the known corpuscles. 



Because reactions may follow transfusion if the bloods of donor and 

 recipient are incompatible it is advisable to apply these preliminary 

 tests; the technic is described on page 311. 



With the increasing number of blood transfusions, the phenomena of 

 isoagglutination and isohemolysis the two being closely related are 

 of considerable practical importance, especially if the patient is suffering 

 with cancer, when the serum is likely to be actively hemolytic for the 

 donor's corpuscles. 



In selecting the donor for a transfusion, agglutination and hemolysis 



