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BIOLOGY: GENERAL AND MEDICAL 



groups according to the interaction of their serums and 

 red corpuscles. The differences make their appearance 

 when the individuals are about one year old, and are 

 permanent and hereditary The groups may be shown 

 in tabular form thus: . 



Serums 

 Groups I II III IV 



By examining the table it becomes evident that the 

 serums of members of Group I are without injurious 

 effect upon any corpuscles and that the individuals of 

 this group can, therefore, receive them from any donor. 

 Cases falling in Group I may, therefore, be described as 

 "universal recipients," and Karstner has shown that about 

 3.1 per cent, of human beings are so constituted. 



It is also evident that the corpuscles of cases falling in 

 Group IV are not affected by the serums of any of the 

 other groups and can, therefore, be given to any patient 

 needing them. Cases falling in Group IV are, therefore, 

 capable of acting as "universal donors," and Karstner finds 

 that about 46.2 per cent, of human beings fall into this class. 



Difficulty arises when the individuals to be transfused 

 or the donors of the corpuscles fall into Group II, of which 

 there are about 42.4 per cent, among human beings, or 

 Group III, of which there are about 8.3 per cent, of human 

 beings according to the same author. 



Theoretically, members of Group II can receive cor- 

 puscles, with benefit, from Groups II and IV only; mem- 

 bers of Group III, from Groups III and IV only, and 

 members of Group IV, from Group IV only. 



