26 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
Several pints of the horse’s blood are now drawn off with a 
sterile needle and allowed to clot, and the clear fluid or serum 
which soon appears is found to contain diphtheria antitoxin, 
i.e., Substances which have the properties of neutralizing the 
poison or toxin of diphtheria. This antitoxic serum is injected 
into diphtheria patients. 
It must be clearly understood that the horse suffers 
practically no discomfort, and remains in perfect health. 
Indeed, if its health was not perfect, the amount of antitoxin 
manufactured would be greatly diminished. Tetanus antitoxin 
is made in the same way. 
Diphtheria antitoxin is extensively used in treatment of 
diphtheria in every civilized country im the whole world. 
The treatment has saved hundreds of thousands of lives, 
and it is based upon scientific principles which are absolutely 
unassailable. | 
The value of diphtheria antitoxin can be proved in another 
way, if ten guinea-pigs are divided into two batches of five 
each, and one batch is oculated with diphtheria toxin alone, 
and the other batch is inoculated with diphtheria toxin and 
diphtheria antitoxin together, the first batch will all die and 
the second batch will all live. | 
Ignorant critics say that diphtheria antitoxin is useless, 
because in certain great cities the total number of deaths from 
diphtheria has not greatly dimimished. This is no reflection 
whatever on the value of treatment, because the crowding 
together of people in the cities increases the number of | 
cases of diphtheria, consequently, even though a relatively 
smaller number of the infected die than formerly, yet the 
death-rate is not diminished to the same extent as it would 
be if there was no increase in the number of cases. One might 
just as well argue that life-boats are no use for saving sailors 
from shipwrecks, because the number of sailors drowned on a 
particular coast has not greatly diminished, since the intro- 
duction of life-boats! 
