S toward. — On Endospermic Respiration in Certain Seeds . 427 
Pure Endosperms (Series ‘ B ’, Winter Experiments). 
Material derived from germinated seeds. 
E;xp. 37. Intact seeds steeped in (1) 3 % CuS0 4 , 2 hours; (2) water, 48 hours; and 
then germinated on moist blotting-paper under bell-jar for 3-4 days; 
embryo then excised, and spermoderm and aleurone layer stripped off with 
forceps. 
No. of 
objects. 
Wt. 
grms. 
Vo/, 
c.c . 
Temp . 
C.° 
After hours 
of 
respiration. 
co 2 %. 
or/- 
Mgms . 
C0 2 . 
COJO % 
25 
I.043 
2*5 
21° 
4 
1-711 
16-92 
0-01935 
°-67 
2-25 
1 8° 
6 
1.974 
16-33 
0-01307 
o-S3 
Exp. 38. Intact seeds steeped in (1) 3 % CuS0 4 , 2 hours ; (2) water, 48 hours ; and 
then germinated, as described in the preceding experiment, for 6 days; 
embryos then excised, and spermoderm and aleurone layer stripped off 
with forceps. 
35 i*4i3 3* 1 l8 ° 3 I-90 1 1 7*47 0-02562 0-75 
5 . Experiments with Seeds of Zea. 
The earlier series of respiration experiments with Zea having been 
undertaken with material of unsatisfactory germinative powers, it was 
considered desirable to practically subject the matter to a re-investigation. 
Hence, the work here recorded represents the results obtained with 
a reliable sample of the ordinary maize of commerce possessing a satis- 
factory germinative capacity. 
While adhering to the methods of experiment already indicated under 
Hordeum for the preparation of sterile material, only the stronger (6 %) 
solution of copper sulphate was employed in this series of experiments, 
and the duration of the steeping period was considerably extended. 
Aqueous solutions of o-i % and 0-5 % mercuric chloride were also used in 
certain experiments in dealing with pure endosperms either for short steep 
purposes, or for rinsing the experimental material. Similarly, aqueous 
c-i-o-4 % solutions of formaldehyde were freely used for washing purposes 
where their employment appeared to offer advantages. Experiments were 
also instituted in which saturated aqueous toluene served as the steeping 
medium. 
Most of the experiments were performed within a comparatively small 
range of temperature, i7°-2i°C., a modern forcing-tray, provided with 
a thermo-regulator, being used for this purpose. 
In every instance great care was taken during the various manipulative 
operations to avoid accidental contamination, all these operations being 
carried out in a sterilized chamber. 
Gg 
