82 BOTANICAL GAZETTE [FEBRUARY 
RESPIRATION IN ANIMALS. 
Upon undertaking special consideration of this topic, I found it 
needful to examine the recent literature of respiration in animals, 
the aspect of the general subject with which I felt myself least 
familiar. I found, to my very great surprise, that animal physi- 
ologists have concerned themselves very little with the essential 
problems of respiration. They seem to have been diverted to the 
study of the mechanism of gas movements in the higher animals. 
The lungs, with their intricate structure of lobes, lobules, atria, and 
air “cells;”” the box in which the lungs are located, with its com- 
plex muscular mechanism, and the very complicated mechanism of 
innervation for the voluntary and involuntary movements which it 
executes; the blood, and the physico-chemical relation of the gases 
that enter and leave it in the lungs, of those that come into it from 
the tissues, and of those it gives up to the tissues—these are the 
topics that one finds exploited at length when he turns to the text- 
books. I diligently examined the most modern and most thorough 
text-books on animal physiology; such books as Foster’s Physi- 
ology; STEWART’S Manual oj Physiology; the American Text-book 
of Physiology; and SCHAEFER’s Text-book of Physiology; but in 
them I found no treatment whatever, indeed no mention whatever, © 
of the real problems of respiration, that is, of what is happening in 
the tissues—the processes of which these external phenomena are 
the sign. Yet this much-studied respiratory mechanism, which is ~ 
so striking in the higher animals, is entirely wanting in the lower — 
animals and in plants. 
Not finding even a clue to the literature in the text-books, it was 
_ only after much search that I was able to discover that anything at 
all had been done; and it is so little that it is almost a negligible 
quantity. There is an obvious reason for this, beside mere interest 
_in the more striking phenomena. I am intending, however, neither 
arraignment nor excuse, but a bare statement of what were to me 
RESPIRATION IN PLANTS. 
aoe ‘The knowledge of respiration in plants began about the same 
- time—the os of the ear century—and advanced d rapidly 
