Stoward. — On Endospermic Respiration in Certain Seeds. 447 
In each instance the deviation from the mean value is comparatively 
small. 
The determination of the oxygen percentages has not presented any 
difficulty ; in every instance where oxygen was the only gas remaining for 
analysis, as, for example, in the experiments with material steeped in 
aqueous chloroform, toluene, or formaldehyde, the difference in the per- 
centage composition at the commencement and end of the experiment may 
be regarded as being due to the passive absorption of the gas by the 
material. 
In the earlier series of experiments with chloroform-steeped endosperms 
of Hordeum it was recognized that the subsequent complete washing out 
of this reagent might be difficult to accomplish, or, on account of its de- 
composition under the influence of light yielding chlorine and hydrochloric 
acid, the analysis of the C 0 2 percentage might be vitiated to some extent. 
In order to settle this point the following direct experiment was made. 
A mixture of 20 volumes of air and 7 volumes of saturated aqueous 
chloroform was introduced into the calibrated tube of the apparatus, 
thoroughly mixed, and then appropriate quantities of the absorbent solutions 
were added. 
The result of this experiment is given in the following tabular state- 
ment, and shows that no decrease in volume occurs, which would render 
the percentage result for C 0 2 too high ; on the contrary, a slight increase 
ensues, which is in agreement with the fact that when chloroform is treated 
with a 40 % solution of KOH evolution of C 0 2 takes place : — 
Vols. of air and saturated 
aqueous chloroform in- 
troduced into apparatus. 
Vols. of gaseous 
mixture after 
mixing. 
Vol. after 
addition of 
KOH solution. 
Vol. after 
addition of 
pyrogallol solution. 
20.4 air 
22-0 
22.45 
18.30 
7 aq. chloroform 
22.50 
18.30 
mean = 
22.47 
18.30 
Conclusion. 
From the results which the investigation has furnished the following 
summary appears to be justified : — 
1. When the pure endosperm tissue of both Hordeum and Zea> 
prepared in a manner which precludes the possible diffusion of respiratory 
enzymes from either the embryo or aleurone layer, is placed under appro- 
priate conditions, it is capable of manifesting a gaseous exchange of 
a respiratory character. Whether this manifestation of respiratory activity 
is due wholly or in part to the vital activity of living protoplasm, or to the 
