220 THE STRUGGLE FOR LIFE. 
taking food into its body. They are also able to change 
their shape in the same way. 
I am now going to speak of the changes seen under the 
microscope, when the web of a frog’s foot is lightly touched 
by the point of a hot needle. The current of blood pre- 
viously flowing through the capillaries stops at once, and 
they become filled with a mass of red disks and white 
cells mingled indiscriminately together. The frog’s foot is, 
however, hardly transparent enough for the examination of 
the minuter changes, so that other tissues have to be used 
for further research. It will then be found that the white 
cells, which are still living and active, actually pass through 
the walls of the capillaries, and they do not seem to pass 
through pre-existing openings, but through the nearest part 
of the vessel. The white cells, apparently reinforced 
by the nuclei of the connective tissue cells, of which I 
have already spoken, range themselves between the living 
and dead tissue. The same thing happens when foreign 
substances have entered the body. But this is not all, 
when the irritating particles, such as Bacteria, are very 
small, the white cells proceed to eat up, or include in their 
own bodies, the dead or foreign particles which would be 
injurious to the body, from this they have been called 
Phagocytes, from the two Greek words, phagein, to eat, 
and kutos, a cell. These cells, after having performed their 
office, that is, by destroying the invaders, or eating up the 
damaged structures which they have rendered harmless, 
themselves die, and are gradually absorbed. If present 
however in too great numbers, they cannot be removed by 
absorption, and the dead soldiers or policemen, as they 
may be styled, collect together to form an abcess, this 
makes its way to the surface by the easiest route, and this 
progress is effected by the same process of local death, and 
by the eating up of the dead material. If, however, the 
abcess is so situated that it cannot make its way to the 
+). 
