The Effect of Chloroform upon Respiration 
and Assimilation . 1 
BY 
ANNIE A. IRVING, 
Newnham College, Cambridge. 
With Twenty-four Figures in the Text. 
N UMEROUS scattered observations have been made on this subject, 
but there has been no systematic study of the effect of different doses 
of an anaesthetic upon respiration and assimilation. The object of this 
research has been to obtain satisfactory data on this subject. In work of 
this kind a single estimation of the respiration after a dose of anaesthetic 
is of very little value; therefore in all cases the effects of the dose have 
been followed for many consecutive hours. These long sequences of 
observations were rendered possible by using the apparatus designed by 
Dr. Blackman, and referred to in my previous paper, No. VII of this Series. 1 
Throughout the work isolated leaves only have been employed, chiefly 
those of young Barley shoots and of Cherry Laurel. These were freshly 
cut for each experiment, enclosed in glass chambers through which a con¬ 
tinuous current of air was drawn, and experimented upon at a temperature 
of 25 0 C. 
The data obtained for the effect of different doses of chloroform will be 
presented in three separate sections. The two sections constituting Part I 
deal with (i) the effect of single doses of chloroform on respiration, and 
(ii) the effect of continuous treatment with chloroform. Part II deals 
with the effect of chloroform upon assimilation. 
As the series of respiration estimations in each experiment lasts some 
time and the leaves are in most cases in the dark, starvation effects cannot 
be neglected. Numerous control experiments without anaesthetics have 
made clear the normal course of the respiration of the leaf starved in the 
dark. Under such conditions there are always considerable fluctuations in 
the successive respiration-readings, but in the large number of controls 
1 This paper constitutes Part X of Experimental Researches on Vegetable Assimilation and 
Respiration. The recent papers of this Series, carried out at Cambridge under the general direction 
of Dr. F. F. Blackman, are : VII, A. A. Irving : The Beginning of Photosynthesis and the Develop¬ 
ment of Chlorophyll, Ann. of Bot., vol. xxiv, Oct., 1910; VIII, Blackman and Smith : A New Method 
for estimating the Gaseous Exchanges of Submerged Plants, Proc. Roy. Soc., B, vol. lxxxiii, 1911 ; 
and IX, Blackman and Smith : On Assimilation in Submerged Water-Plants, and its Relation to the 
Concentration of Carbon Dioxide and other Factors, Proc. Roy. Soc., B, vol. lxxxiii, 1911. 
[Annals of Botany, Vol. XXV. No. C. October, 1911.] 
