250 BOTANICAL GAZETTE [NOVEMBER 
plete trains to provide for, it was not deemed practicable to apply 
the type of automatic pipette arrangement used by BAILEy and 
GurRjaR (9). Instead, a large bottle was thoroughly cleaned and 
aerated with carbon dioxide-free air and filled with the standard 
alkali. This reservoir was connected by tubing with a burette, 
and communication with outside air protected by soda lime traps. 
At the top of each of the bead tower columns was placed a separa- 
tory funnel guarded by a soda lime trap. Before each running the 
required number of cubic centimeters of the alkali were run directly 
into the separatory funnel previously washed free of carbon dioxide. 
When the whole outfit was ready to make a running, carbon 
dioxide-free air was run for a sufficient period through the bead 
tower column to remove all carbon dioxide, before admitting the 
alkali from the separatory funnel directly into the bead column. 
This method of determination of carbon dioxide is essentially that 
described by TRuoc (54). Varying periods of aspiration in these 
measurements were employed, although experience showed that 
most satisfactory results could be obtained by employing a period 
of from four to five hours. No results were considered worthy of 
recording for second runs of any one lot of samples, as experience 
showed the need of extreme care to avoid introducing errors inci- 
dent to the growth of saprophytes upon the check samples, par- 
ticularly if they were retained at 28°C. longer than one day. 
BarLey and GuryjAR (g) allowed their moist wheat to stand several 
days before removing the stagnant air for carbon dioxide determina- 
tion. Had they used the temperature of 28°C., and had their 
seed possessed a moisture content of 35-43 per cent, as was the case 
in these tests, it would have been impossible to avoid questioning 
the lary factor of saprophytes which these experiments showed 
increased tremendously the output of carbon dioxide. Disregarding 
the fact that they failed entirely to keep their chambers aerated 
during the course of their work, however, it must be said that they 
incubated their seeds at 37.8° F., and worked with seeds of moisture 
contents much lower, in general between 12 and 20 per cent. NABO- 
KICH (41) concluded that part of the carbon dioxide obtained in 
plant respiration is incident to the same microorganisms that 
vegetate on leaves and seeds. It was hence a source of much 
