AMERICAN NATURALIST 
VOL XXVILI. January, 1893. 313 
THE GASES IN LIVING PLANTS: 
By J. C. ARTHUR? 
The present state of knowledge regarding the kinds, sources 
and movement of gases in plants does not constitute a com- 
pleted volume. There is much yet to be learned, old views 
are to be corrected, and alleged facts are to be more firmly 
established. The subject is thoroughly modern, the first 
writer to give any connected and intelligent account of the 
behavior of gases in connection with living plants being De 
Saussure in his brilliant and epoch-making work describing his 
chemical researches upon vegetation, published in 1804. 
THE COURSE or Discovery UP To 1865. 
The various life functions of plants have been slowly estab- 
lished by first assuming them to be individually the same as 
those of animals, and from this basis gradually evolving their 
true nature. The early naturalists saw nothing in plants that 
suggested lungs or the movement of air, and it was not till the 
time of Malpighi, 1671, that breathing was supposed to have 
any part in the plant economy. He saw in the wood vessels, 
known then and long afterward as spiral vessels, an analogous 
1 Read before the Biological Section of the Amer. Assoc. Adv. Science, in Wash- 
ington, August, 1891. 
? D, Sc. Professor of Vegetable Physiology and Pathology, in Purdue University, 
Indiana. 
T 
