aa Sh ee a ee ee ee ee ee eee ee ee eh a ee tae ty eed CP ee 
ae eo = 
200 MISSOURI BOTANICAL GARDEN. 
in 50% alcohol). The tubes were boiled, cooled, and the 
plants introduced. They were then tightly stoppered and 
placed in the light of a south window. , 
February 6. After nearly a month the blanks remained 
colorless. This showed that the alkalinity did not come from 
the excretions of the plants themselves, as it had been claimed 
by Loew. All the tubes containing both plants and sodium 
bicarbonate turned deep red on bright days, and faded during 
the night or cloudy days, which were numerous enough at 
that time. Spirogyra, alone, gave little or no color, owing, 
apparently, to its poor condition. The intensity of the color 
varied with the plants in the order named, Elodea giving the 
deepest, and Spirogyra the faintest. There seemed to be 
little, if any, difference between the 0.1% and 0.2% solu- 
tions. The results were in all essential respects similar to 
those in the solutions of lime-carbonate. 
Cultures prepared in the same manner, but using potassium 
bicarbonate, gave even more decided results. This is all the 
more significant since cultures with potassium nitrate, instead 
of carbonate, failed to give any color, as Loew claimed, but 
soon died, instead, and became infested with moulds. In so 
far this indicated that the important thing is the carbonate 
in the production of alkalinity. 
February 2 to March 2. A similar set of experiments, 
using ammonium-carbonate, resulted only in the death of the 
plants. This was likely due to the toxic effect of the 
ammonium which, according to the experiments of Living- 
ston (’05), is five times as toxic as the above cations in the 
same concentration, and also Andrews (’05) showed that 
hairs of T'radescantia virginica were killed if left longer than 
one minute in a one per cent solution of ammonium-car- 
bonate, and were affected adversely in a 0.5% or 0.25% 
solution of the same. 
Another set of cultures like the above, but containing 
manganese carbonate, although run for nearly a month, gave 
no color. This is probably due to the low degree of solubility 
and dissociation of this compound. 
One of the strongest arguments against the theory of Loew 
Fe ee eS es Oe yt ee 
