THE PATH OF EVOLUTION 



powers life depends, there are present in much smaller 

 numbers the white corpuscles. There is in health 

 only about one of them to over three hundred and 

 fifty of the red, but their aggregate number exceeds 

 one thousand million in the blood of an average man. 

 When viewed ordinarily under the microscope, they 

 are seen to be colorless globules of protoplasm, a 

 little larger than the red corpuscles. If the drop of 

 blood containing them is warmed up again to the 

 normal blood temperature, they are then seen to be 

 full of life, and are, or at least closely resemble, 

 Amceba. They throw out their substance into con- 

 stantly changing forms (Pseudopodia) or limb-like 

 extensions. They move independently from place to 

 place, and seize upon particles in the fluid which they 

 absorb into their substance. They pass into all the 

 vessels of the body by means of their contractile 

 power of changing shape through apertures far 

 smaller than their original form. (Dr. Johannes 

 Kanke, " Der Mensch," Leipsig, 1887. B.I. S. 225). 

 Legrand and Leville* describe experiments made 

 with the white corpuscles (Leucocytes) and the Bacil- 

 lus Subtillus, in which they have seen the Leucocytes 

 seize and absorb the bacilla. Other Leucocytes then 

 join the first, and attack and absorb as many bacilla 

 as they can. Those thus absorbed would completely 



* Larousse. Art. Phagocytes, 1889. 

 224 



