WOliK ANT) WASTE. THE JiLOOD. 



53 



Fig. 27. 



RED CORPUSCLES OF HUMAN 

 BLOOD (400 Diameters). 



than water. If we look at a drop of it through a micro- 

 scope, we shall see in it many small round bodies, shaped 

 like a coin with a thick rim. These 

 are only M W f an mcn across, and 

 are all of the same size. They are 

 called red-blood corpuscles, or glob- 

 ules. They make up nearly half the 

 blood. 



2, Every animal that has a back- 

 bone has red globules in its blood, 

 but they differ in shape and size. 

 In birds and reptiles they are not 



round, but oval, in shape, and have a spot in them called 

 a nucleus. In all animals that have round globules, they 

 are smaller in size than 

 those of a man's blood, 

 with two exceptions, the 

 elephant and the sloth. 



3, We know by careful 

 measurements the exact 

 size of these globules in 

 many animals. By ex- 

 amining a drop of blood 

 with a microscope, we can 

 often tell what animal it 

 came from. 



4, Such examinations are made of blood found on the 

 clothing of persons accused of murder, and aid in deter- 

 mining their guilt or innocence. But this evidence 

 should not be accepted as decisive. There are possibili- 

 ties of mistake. 



5, Besides the red corpuscles, there are also white cor- 



Fi. 28. 



RED CORPUSCLES or FROG'S BLOOD (400 

 Diameters). 



