312 
FREDERICK A. LYONS- 
a vacuum. That the atmospheric pressure exercises the greatest 
influence in this process is easily observed, for where the air is 
rarified and its pressure diminished, as is the case at a high alti¬ 
tude, the chest expands more fully and a larger volume of air is 
aspirated into the lungs at every inspiration. 
And so we might adduce instance after instance, but these 
will suffice. Yet, since I have only spoken of these simple and 
well known examples of the application of the laws of chemistry 
and physics, it might seem at first sight that the relation was 
limited, and that a superficial acquaintance with these laws would 
be sufficient for the comprehension of all physiological problems. 
Nothing could be farther from the truth. These laws have an 
infinite application. The most intricate vital manifestations can 
only be explained by a reference to them. They all have a 
chemical and physical basis. Even the most complex phenomena 
of the nervous system may be interpreted by their means. The 
highest and most subtle of all, the very process of thought and 
ideation, has, as to its immediate cause, some chemical or physical 
change, or both combined. Alexander Bain and other philoso¬ 
phers of his school have even pointed out with an accuracy, which, 
if it be not absolute, is certainly very probable, how a chemical 
and physical change may be transmuted into a distinct, living idea. 
But I think I have said enough to convince those most unwil¬ 
ling of conviction, of the great importance to medicine of the 
study of chemistry and physics. A knowledge of these branches 
should properly be obtained in the preliminary education, and 
they should be thoroughly acquired before the student commences 
his more special studies. They should not really have to be 
included in the medical curriculum, but unfortunately we find 
very few who come so well prepared, and so they have to he 
taught side by side with the more directly practical branches. 
Is it requisite that I should dwell at any length upon the 
importance of the §tudy that should come next in order, that of 
comparative anatomy ? Its necessity should be so obvious that 
one would think its mere mention would be sufficient, and yet it 
is not so. Students are in such haste to learn how to recognize 
disease and to cure it, especially the latter, that they often sadly 
