smoking do, that the use of tobacco is univer- 
sally harmful. 
Fourthly, the conclusions arrived at by some 
investigators, are based on experiments made 
on animals, and it appears quite open to criti- 
cism, and is in fact disproved by common ex- 
perience, that such results will follow when ap- 
plied to man. Hinging on this is the question 
of immunity and toleration. The human system 
will easily after use tolerate effects which at 
first it rebels against. This may easily be seen 
in muscular and other efforts. Let a man who 
is constantly leading a sedentary life suddenly 
walk 10 miles. The result is almost prostration 
and he will not recover from it for a consider- 
able time. Let him, however, commence by 
walking a mile or two and gradually at each 
walk increase the distance, and in a short while 
he will be able to walk 10 miles without feeling 
any fatigue. Similarly running or other rapid 
exercise to a person not used to it will produce 
such rapid disturbances in the respiration and 
circulation as even to be fatal, while the sea- 
soned athlete may perform such feats without 
the least ill effects. 
To take animals or persons who have never 
before used tobacco and to argue or conclude 
that the effects of tobacco smoke on them are 
the effects of tobacco on smokers generally is 
177 
