BACTERIOLOGY AND THE WAR. lure 
But the body also destroys the bacteria and their 
poisons by the blood plasma, for it contains antibodies or 
substances which are antagonistic to the bacteria. The 
properties of these substances are wonderful, some drive 
the bacteria into clumps or concentration camps, from which 
they cannot emerge to devastate the surrounding country ; 
some dissolve the bacteria as water dissolves sugar; some 
neutralize the poisons or toxins of the bacteria, in a manner 
somewhat resembling the neutralization of acids by alkali. 
these are the antitoxins. Another substance, the most 
remarkable of all, coats the bodies of the bacteria so that 
they become appetizing for the phagocytes to swallow. This 
substance is called opsonin. tis a sauce or butter which covers 
the microbe, making it attractive for the phagocyte. Further, 
each kind of bacterium requires a special type of opsonin or 
sauce, if the best results are to be obtained. The opsonin 
for the tubercle bacillus is different from the opsonin for the 
typhoid bacillus. The phagocyte is fastidious, it does not 
like Worcester sauce with plum pudding. 
The phagocytes and blood plasma are brought to the 
battle-field by railway lines, namely, the arteries. But suppose 
the railways are not large enough to bring sufficient troops 
to repel the enormous number of invaders, what then? The 
body is able to double or treble the size of the railways by 
dilating the arteries so that much larger reinforcements of 
plasma and phagocytes are hurried to the front. Thus the 
inflamed part becomes red, because the arteries have enlarged 
to brmg up more blood; the inflamed part becomes swollen, 
partly on account of the enormous quantities of phagocytes 
and plasma passing into the tissues and partly on account 
of the accumulation of their dead bodies in the form of pus 
or “matter”; the inflamed part is painful, partly because 
the poisons of the bacteria irritate the nerve endings. This 
is no fancy picture, but is capable of scientific proof, 
