64 
fluence of cold, of a condition to which he was not accustomed and perhaps 
wholly unadapted. If, on the other hand, we take an inhabitant of the 
frigid zone and put him in a warm country, we would in all probability 
find another series of complaints. In the temperate zone where there is 
an alteration of heat and cold, one might say six months of tropical life 
and six months of arctic life, many individuals cannot adapt themselves 
to this semi-annual change, and as a consequence they suffer. 
Again, the individual who has been brought up on plain, substantiai 
food in the country, free from all infectious matter, may complain greatly 
if confined to the food obtained in the city, which has passed through 
many hands. The milk which so well agreed with him in the country may 
be a veritable poison to him in the city; even the drinking-water may 
disagree. 
We see this again illustrated in the matter of air conditions. The 
man who has always lived under good air conditions, and whose ancestors 
have lived under such conditions, may complain greatly on removal to a 
dirty city where the air is loaded with dust derived from different sources, 
partly from the bodies of those who are diseased. Such an individual may 
have a sound body and may have sound health under his proper environ- 
ment, but he may complain in the city simply because his body reacts to 
the abnormal environment. Thus, if he inhales much dust, there may be 
cough 
nature’s way of getting rid of offending material. The dust may 
set up a profuse flow of mucus, resulting in so-called catarrh—and yet 
this may be simply a natural reaction of the body in protecting the res- 
piratory organs and in getting rid of the inhaled dust particles, which are 
brought up with the mucus in the process of coughing and hawking. Vari- 
ous pains may come on, yet they are to be looked upon as warnings from 
nature—to change the environment. When an individual does change and 
finds all these symptoms of illhealth (not of real disease) disappear, 
that ought to clearly indicate to him the conditions under which he should 
live. If he persists in living under the abnormal environment, we know 
what will happen: nature is constantly weeding out the unadapted—a 
process that has been going on for countless ages, and still continues. The 
doctrine of the Survival of the Fittest is a terrible reality from the stand- 
point of the biologist and physician. 
One may come into a new environment and discover that there is 
a non-adaptation. The thoughtful man will see two courses open; first, 
