Steward . — On Endospermic Respiration in Certain Seeds . 419 
The duration of the steeping operation was varied considerably. At its 
termination the experimental material was superficially dried, by placing it 
on or between folds of sterilized blotting-paper, and then quickly transferred 
to small tarred cylindrical respiration-tubes, having a total capacity of 
approximately 10 c.c., and graduated in divisions of 0-5 of a c.c. Each 
tube was plugged with a sterilized cotton-wool plug. The weight of the 
material was then ascertained, the plug at once removed, and the respiration 
experiment commenced by inverting the tube over mercury contained in 
a small dish. 
Where necessary, a small quantity of water — one or two drops — was 
introduced by means of a small curved capillary pipette to ensure the 
maintenance of the material in a moist condition. At given intervals 
specimens of the gaseous respiration products were removed, by placing the 
respiration-tube in direct communication with the graduated tube of the 
apparatus employed for carrying out the analysis. 
The gas analyses were made with the improved Bonnier-Mangin 
apparatus, by means of which very small volumes of gas can be subjected 
to analysis. This apparatus is particularly serviceable in cases where only 
small quantities of gas are available. For the absorption of C 0 2 and 0 2 
a 40 % solution of KOH, and a cold saturated aqueous solution of pyrogallol 
diluted to one-tenth its original strength, were respectively employed. This 
latter solution was either freshly prepared as required, or on every second 
day. To avoid the decomposition of the pyrogallol with evolution of 
carbon monoxide (which occurs when the caustic potash solution is not 
used in sufficient excess), the analyses have been so performed that the 
ratio of the volumes of the alkali and pyrogallol solutions was 2:1. There 
is also a distinct advantage in employing these reagents in such total 
quantity (which can be experimentally determined) that neither is in large 
excess relatively to the quantities of the gases to be absorbed : the subse- 
quent washing out of the apparatus on the completion of the analysis being 
thus rendered more expeditious. 
3. Experiments with Seeds of Hordeum. 
These were undertaken with a well-matured Chilian barley which 
consisted of a mixture of H. vulgar e and H. hexastichum of the year 1904, 
and possessed a satisfactory germinative capacity. 
The general method of preparation for intact seeds, 1 embryos, and 
endosperms was the following : — 
Intact seeds were washed in running tap-water for a quarter to half an 
hour, then steeped in 3 % or 6 % copper sulphate for periods of one to three 
hours, and finally were thoroughly washed with, and steeped in, sterilized 
1 For convenience the term ‘seed’ is used throughout to imply the fruit or caryopsis of the 
Gramineae. 
