THE PRESIDENT'S ADDRESS. 
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that Descartes is the thinker above all others who stands in this 
relation towards the Science and Philosophy of the modern world ; 
that in any characteristic product of the modern ways of thinking 
you will find the spirit of that thought, if not its form, to have 
been present in the mind of the great Frenchman. 
Descartes, living as he did about the time of the celebrated 
Harvey, was acquainted with his researches into the method of 
the circulation of the blood, and was evidently much impressed 
thereby, as he describes it more than once in his works, and he 
adopts a physico-mechanical view of the way in which the 
functions common to man and animals are performed. He 
looked on consciousness as the peculiar distinction of the chose 
pensante of the rational soul, which in man — and in man only 
according to Descartes — is superadded to the body. 
He thought this rational soul to be lodged in the pineal gland — 
a small structure at the base of the brain — as a sort of central 
office, and that here, by the intermediation of the animal spirits, 
it became aware of what was going on in the body, or influenced 
the operations of the body. Matter, according to Descartes, is 
substance which has extension, but does not think ; spirit is 
substance which thinks, but has no extension. He said, Coglto, 
ergo sum, " I think, therefore I am." Thought, then, is 
Existence. 
Huxley, although criticising this assertion, says that the method 
or path which leads to truth, indicated by Descartes, takes us 
straight to the Critical Idealism of his great successor Kant. It 
is that Idealism which declares the ultimate fact of all knowledge 
to be consciousness, or, in other words, a mental phenomenon, 
and therefore affirms the highest of all certainties — and indeed 
the only absolute certainty — to be existence of mind. Eouillier 
says that Descartes has merited the title of the father of physics 
as well as that of the father of modern metaphysics. 
Doubtless all present have heard, more or less vaguely, of the 
wonderful microbes, spores, bacteria, and the like, which surround 
us on every hand. Although it has long been suspected that 
many diseases were due to the presence of minute forms of life, 
which multiplied very rapidly, still until quite recently no proof 
had been forthcoming. The investigations of Tyndall into the 
existence of germs in the air, which undoubtedly are the causes 
