DEFENSE BY WHITE CORPUSCLES 271 



cell-eaters. They are also called leucocytes, a 

 word meaning white cells. They are white cells 

 themselves; and they devour disease germs, which 

 are much smaller cells. 



The Whites feast on the disease germs as a choice 

 morsel. Fig. 106 shows a white corpuscle having 

 just come in contact with a disease germ. 



Fig. 107 shows a cavity forming in the corpuscle, 

 with the germ being drawn into it. 



In Fig. 108 the germ is enclosed. In Fig. 109 

 the germ is digested, absorbed, assimilated, and the 

 phagocyte is ready for another feast. 



A wound occurs somewhere on the body. Bad 

 germs come into it from the air. They begin to 

 grow, multiply and produce poison. But at this 

 moment white corpuscles flock to the wound and 

 devour the invaders in great numbers. If their 

 work is sufficient, the wound heals without blood- 

 poisoning. If not, in the absence of other anti- 

 septics, the poisoning may be serious. 



One is taken by some contagious and infectious 

 disease. The germs enter the circulation, and mul- 

 tiply at a great rate. But here they are met by 

 the white corpuscles and devoured in great num- 

 bers. If the protection is sufficient, the patient 

 has the disease but lightly, and soon recovers. If 

 not, the patient has a severer run of the disease, 

 and may die. 



This part of Nature's defense, in so far as it goes, 

 is of course ontogenetic, that is, defense in the in- 

 dividual. And the nation, being composed of in- 



