1893.] The Gases in Living Plants. 7 
imaginary “spongioles” upon the root tips, which still have a 
sort of backwoods existence in the minds of some persons, 
although practically eradicated from the text books. He sub- 
scribed to the dual respiration of plants by which they gave 
off oxygen in daylight and carbon dioxide in-darkness, which 
is still taught by certain American text books. In other 
American text books, which are still standard, a reaction is 
shown by the suppression of any suitable account of respira- 
tion proper, this important subject being referred to only inci- 
dentally in a line or two in connection with a short account 
of the use plants make of stored food material. Thus, in the 
latest revised edition of Gray’s Lessons in Botany, as in the 
preceding edition, barely three lines are devoted to respiration, 
while two pages are given to assimilation. This work also 
teaches the incorrect doctrine’ that carbon dioxide beside 
reaching the plant through the surface of the leaves, “is 
absorbed by the roots of plants, either as dissolved in the 
water they imbibe, or in the form of gas in the interstices of 
the soil.” In Bessey’s Botany, first issued in 1880, respiration 
is treated in essentially the same brief manner, and it is 
curious to note that the unusually complete index to the work 
does not contain the words gas, breathing, or respiration. 
The modern phase of plant physiology may be said to have 
been introduced to English speaking students by the transla- 
tion of Sach’s text book in 1875, and reinforced by the appear- 
ance of Goodale’s work in 1885, on this side of the Atlantic, 
and of Vines’ work the following yearin England. In these 
works the balance between respiration, assimilation and the 
physical movement of gases is fairly well maintained. 
Another work in English, less pretentious, but equally accu- 
rate and discriminating with the last mentioned, and antedat- 
ing them, should be spoken of here, that of Johnson’s How 
Crops Feed, published in 1870. The work was deservedly 
popular, and is still a source of exact information. 
5In the discussion which followed the reading of this paper, Prof. Geo. L. Goodale 
gave Dr. Gray’s reasons for retaining his early views. It was Dr. Gray’s belief that 
his statement would prove, upon more extended investigations, to be essentially cor- 
rect. Prof. W. H. Brewer spoke in further support of the conservative views of 
Dr. Gray. 
(To be continued.) 
