ISOAGGLUTININ AND ISOHEMOLYSIN 93 



would be explained on the same basis. While Jansky's methods 

 have priority in time of publication the American surgeon has 

 during the great war become accustomed to the Moss grouping 

 which is as follows : 



Serum 

 Cells I II III IV 



I + + + 



II + + 

 HI + + 

 IV 



It will be seen that this is merely the reverse of the first one and 

 that Type IV has agglutinins but no agglutinable bodies. 



Agglutinins and agglutinable bodies may be absorbed from a 

 given blood by saturation with their respective antigen. 



In transfusion, homologous bloods should be mixed, but groups 

 I or IV respectively may be considered as universal donors since 

 experience shows it safe to use a blood which agglutinates the 

 recipient's cells. It is however, incorrect to use a blood whose 

 corpuscles are clumped by the recipient's serum. The agglutina- 

 tive titer of human blood is not very high, i-io to 1-25, and as 

 the entering serum is diluted the agglutination titer would be 

 exceeded. 



Further experiments on the independence of the two anti-bodies 

 would indicate that usually agglutination precedes hemolysis but 

 this need not be so, in a small percentage of cases. For practical 

 purposes agglutination tests are sufficient indications of the com- 

 patibility of bloods. Tests for compatibility take the form 'of 

 (i) direct mixture of the blood of recipient and of donor and (2) 

 the testing of donor's blood by standard serums. 



i. Patient's blood A serum separated from the clot. B 

 cells from defibrinated blood washed in saline and resuspended in 

 saline. Donor's blood a serum separated from the clot, b cells 

 from defibrinated blood washed in saline and resuspended in saline. 

 Test A 4 parts b i pt. 

 a 4 parts B i pt. 

 Incubate at 37 for one hour. 



