346 



THE VERTEBRATE BODY 



Type A plasma 



Type B plasma 



cells 



Type 



B 

 cells 



Type 



AB 



cells 



Fig. 23.13. Method of blood typing. A person's blood type may be determined by mix- 

 ing a drop of his blood with plasma from type A blood and with plasma from type B 

 blood. If the blood being tested is type O the cells will be evenly distributed in both 

 cases when examined under the microscope. If the blood is type A the cells will be 

 evenly distributed in the A plasma, but will be clumped together in the B plasma. 

 Type B blood will show just the reverse reaction. Type AB blood will clump in both 



types of plasma. 



