wi - Comparative Physiology of Respiration. 817 
THE COMPARATIVE PHYSIOLOGY OF RES- 
PIRATION: 
By Simon H. GAGE. 
Among the very first of the physiological acts observed 
were those of respiration. The regular movements of breath- 
ing, from the first feeble efforts of the new-born babe until the 
sigh in the last breath of the dying—after which is silence, 
cold and dissolution—have commanded the attention and 
claimed the interest of every-one, the thoughtful and the 
thoughtless alike. And one comes to feel that in some mys- 
terious way “the breath is the life.” But in what way does 
breathing subserve life or render it possible? Aristotle and 
the naturalists of the olden time supposed that it was to cool 
the blood that the air was taken into the lungs, and, as they 
supposed, also into the arteries. With the limited knowledge 
of anatomy in those early days and the fact that after death 
the arteries are wholly or almost wholly devoid of blood, while 
the veins are filled with it, what could be more natural than 
to suppose that the arteries were vessels for the cooling air. 
If one supposes that he has entirely outgrown this view of 
Aristotle let him think fora moment how he would express 
the fact that an individual is descended from the Puritans, for 
example. In expressing it even the physiologist could hardly 
bring himself to say other than “he has the blood of the 
Puritans in his veins.” Would he ever say “he has the blood 
of the Puritans in his arteries?” 
As observation increased the cold blooded animals were 
more carefully studied and found to possess also a respiration ; 
they certainly do not need it fo cool the blood. Then there 
are the insects and the other myriads of living forms that 
teem in the oceans, lakes, rivers and even in the wayside pools. 
Do these too, have a breath? And the plants on the land and 
Address by Prof. Simon Henry Gage, of Cornell University, Ithaca, N. Y., Vice- 
President of the Biological Section of the American Association for the Advance- 
` ment of Science, Rochester, August 17, 1892. 
