12 BOTANICAL GAZETTE [JANUARY 
color. Is chlorosis due to a non-utilization of nitrogen or iron in 
the presence of glucose, or in the upbuilding of chlorophyll is 
glucose less favorable than fructose? Certain experiments now 
in progress may throw some light on this interesting point, and it 
is therefore desirable to await the results before speculating any 
further. 
On January 27 the leaf point was not yet evident in any of the 
plant extract cultures. On March 10, however, in the wheat, beet, 
and potato extracts, embryos with leaf points were apparent, and 
a little later the same was noted for the yeast extract cultures. 
After several months more, seedlings with one and two leaves 
were to be noted in all these cultures. 
Is germination on these extracts due to sugars or to other 
substances? Analyses made of the different extracts show that 
the potato, wheat, and yeast extracts had a sugar content of less 
than 0.025 per cent. The extracts diluted one-half with the 
nutrient solution, therefore, practically speaking had no sugar. 
The beet extract had a sugar content of 0.80 per cent, yet it did 
not permit any better germination than did the potato extract 
with merely a trace of sugar. As indicated previously, it should 
be borne in mind that the beet extract contains some substance 
injurious to the embryo. Furthermore, the stimulating effect of 
the plant extracts when added to the glucose solutions must be 
due to substances other than sugars. In the experiments on the 
influence of concentration of sugar, it will be noted that on the 
concentration of 0.05 per cent no germination has occurred even 
after four months. 
Influence of concentration of sugar 
In view of the fact that germination is possible when sugar is 
supplied in the culture media, it seemed desirable to determine the 
concentration most favorable for growth. Accordingly several series 
of experiments were made, a number of which are here reported. 
In the first experiment seeds of Laelia-Catileya hybrid no. 2 
were used. These were planted November 12, 1920, and notes were 
made December 16, 1920, and January 11, February 15, and March 
15,1921. Each of the average figures given represents the average 
