442 Stoward. — On Endospermic Respiration in Certain Seeds. 
With Ricinus , steeping the endosperm in aqueous chloroform (apart 
from the low temperature of this experiment) apparently leads to a lower- 
ing in the output. 
1 6. Experiments with Toluene-steeped Material. 
Certain experiments with the endosperm of Zea prepared from the 
dry resting seed were performed, the steeping medium being saturated 
aqueous toluene. 
Here, as in the case of aqueous chloroform, the results were distinctly 
negative ; so that, in all probability, toluene exerts a toxic effect on the 
endospermic material of Zea immersed in it for twenty-fours at a temperature 
of 20—21° C. 
17. Experiments with 4% Aqueous Formaldehyde- 
steeped Material. 
Endosperms prepared in the usual way from air-dried seeds of Hordeum 
and Zea steeped in this solution for twenty-four hours invariably yielded 
negative results. 
The effect of formaldehyde in this concentration is not surprising 
when we consider how toxic the action of this reagent is towards living 
protoplasm and enzymes alike. 
Different concentrations of the reagent behave quite comparably with 
that found in the case of aqueous chloroform, as the following experiment 
demonstrates : — 
Endosperms of Hordeum Steeped in Aqueous Formaldehyde 
of Different Concentrations. 
No. of 
endosperms. 
Hours . 
Medium % aq. 
form aldehyde. 
% of medium 
imbibed. 
20 
24 
0-128 
39.00 
20 
24 
0.256 
33*40 
20 
24 
0-400 
32.90 
Here, again, evidence is afforded of the retarding action presented by 
the selective membrane to the entry of water, and presumably the solute, 
into the endosperm tissue. 
In all these instances it seems reasonable to assume that the great 
bulk of these toxic agents enters by way of the exposed proximal end of 
the endosperm, their toxicity depending on the relative amounts which 
enter, the effective maximal amount differing with each reagent. 
