PRESIDENT’S ADDRESS. 1023 
not rise with the evaporating moisture. If they become dry, they 
will be disseminated only by such air currents as are of sufficient 
force to lift them into the atmosphere. This material property of 
gerins then is a fundamental conception, and forms the basis of 
the chief practices of Hygiene in connection with communicable 
diseases. It is a conception too that divests these germs of all 
mystery; it is easily grasped by the public mind, while it is more 
than sufficient to satisty the public judgment on the reasonableness 
of the means prescribed by Public Health legislation for their 
control and destruction. 
The power of these minute bodies or microbes to produce disease 
is beyond dispute. Their vitality is very real, in fact in some of 
them, it is positively tenacious. They attach themselves to 
different structures in the body, find for themselves a suitable soil, 
and multiply with amazing rapidity. The process is not identical 
in each kind, neither are the conditions on which their develop- 
ments is dependent the same in all, but the fact that they are 
living, ponderable bodies, with a life history singularly distinct, is 
applicable to all. It is not assumed that nothing now remains to 
be known regarding them, for that would not be true, but so far 
as public health is concerned, every practical point is covered by 
the knowledge now acquired. 
Tt only remains for me in this first section of my task to say, 
that these germs or microbes are the efficient causes of those wide- 
spread and well known diseases as Typhoid Fever, Diphtheria, 
Tuberculosis, Influenza, and many others, which every year in 
this bright land of Australia destroy so many lives. These 
microbes are known to be specific, they never lose their identity, 
or produce a disease other than the one from which they have been 
derived. They are as separate in their natural history as species 
of animalsand plants are. Their qualities of ponderosity, vitality, 
and specificity render them readily conveyable from one human 
being or animal to another. These attributes also form the basis 
of their infectious or communicable activity, while at the same 
time, having due regard to classification, they guide the selection 
of the means necessary to combat their virulence and stamp out 
the diseases they produce. 
Such knowledge has been gained only by patient and self- 
sacrificing labour, and it is this knowledge which alone can safely 
guide legislation. It can no longer be left out in Public Health 
Administration. Our representatives cannot, therefore, remain 
indifferent to the claims of modern Hygienic Science on behalf of 
the people, neither can they remain any longer unconscious of the 
power they possess to pass intelligent and efficient laws against 
public enemies so subtle, so active, and so mighty. 
