On the Effect of Chloroform on the Respiratory 
Exchanges of Leaves . 1 
BY 
D. THODAY, M.A. 
Lecturer in the Physiology of Plants in the University of Manchester. 
With fifteen Figures in the Text. 
HAT the carbon dioxide evolved in the respiration of plants is of 
X complex origin is now a generally accepted view. It is recognized 
that enzymes play a large part in the processes leading to its evolution and 
also to the absorption of oxygen, which is normally concurrent with it. The 
available evidence seems to show that a close correlation is maintained 
between the rates at which oxygen is absorbed and carbon dioxide produced 
in normal respiration, but the chain of processes is still incompletely known 
and the regulating mechanism a matter for conjecture. It is to be expected 
that a careful quantitative investigation of the temporary increase in the 
intensity of respiration produced by various chemical and other agencies 
may throw light upon the factors which are concerned in keeping the balance 
between the respiratory processes. 
One interesting aspect of the problem that has received little attention 
is whether or how far a close quantitative relation continues to exist 
between the evolution of carbon dioxide and the absorption of oxygen under 
the influence of stimulating agencies. The work of which an account is 
given here was undertaken at Dr. F. F. Blackman’s suggestion with this 
aspect in view. 
There is little doubt that the augmentation produced by different 
agencies is not necessarily of the same nature, even if, as Palladin holds , 2 
the primary effect is always protoplasmic. Miiller-Thurgau and Schneider- 
Orelli 3 found that stimulation due to exposure to a high temperature and 
stimulation following upon injury, in Potato tubers, were antagonistic. 
In the case of an anaesthetic such as chloroform, it may be inferred with 
probability from its chemical inactivity and high degree of saturation, that 
1 This paper forms Part XI of ‘ Experimental Researches upon Vegetable Assimilation and 
Respiration carried out in the Botany School, Cambridge. A preliminary account was given at 
the Sheffield meeting of the British Association in 1910. See Report, p. 765. 
2 Jahrb. f. wiss. Bot., xlvii, 1910. 3 Flora, 1910. 
[Annals of Botany, Vol. XXVII. No. CVIII. October, 1913.] 
