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THE PRESIDENTIAL ADDRESS. 
Another way of estimating the value of prevention is in terms of 
dollars, or pounds, shillings, and pence, and it has lately been calculated 
that the direct loss in England and Wales from sickness and disability 
amounts to at least 150,000,000/. a year. In the United States, with a much 
larger population, the loss is put down at 600,000,0001. 
Another reason why this is an important subject is that medicine in 
the future must change its strategy, and instead of awaiting attack must 
assume the offensive. Instead of remaining quietly in the dressing stations 
and field hospitals waiting for the wounded to pour in, the scientific 
services must be well forward in the enemy’s country, destroying 
lines of communication, aerodromes, munition factories, and poison- 
gas centres, so that the main body of the army may march forward in 
safety. 
It must no longer be said that the man was so sick he had to send for 
the doctor. 
The medical practitioner of the future must frequently examine the 
man while he is apparently well, in order to detect any incipient departure 
from the normal, and to teach and urge modes of living conformable to the 
laws of personal health, and the Public Health Authorities must see to it 
that the man’s environment is in accordance with scientific teaching. 
It may be a long time before the change is widely accepted, but 
already enormous advances have been effected, and it only depends on 
the intelligence and education of the populations how rapid the future 
progress will be. 
Public opinion must be educated to recognise that most diseases are 
preventable and to say with King Edward VII., ‘ If preventable, why not 
prevented 2’ 
To our forefathers disease appeared as the work of evil spirits or 
magicians, or as a visitation of Providence to punish the individual or the 
community for their sins. 
It is not my purpose to give a detailed account of the first strivings 
after a better knowledge of the causes of disease, but it may be said the new 
era began some few hundred years ago, when it was recognised that certain 
diseases were contagious. 
For a long time it was held that this contagion or infection was due 
to some chemical substance passing from the sick to the healthy, and 
acting like a ferment ; and then, about the middle of last century, the idea 
gradually grew that microscopic creatures might be the cause. 
About this time it had been discovered that the fermentation of grape 
