1 24 
Sydney H. Vikes. 
b . Oecasionally in the morning, when the aspirator was in aclion, a 
slight cloudiness became perceptible in the lime-water contained in b", 
bul il was so slight that the solution of polash under the bell-jar c' may 
be considered to have effeclually removed the carbonic acid evolved by 
the plant. 
The apparatus was placed close to a window, but it was never ex- 
posed to direct sunlight. A mirror was fixed behind it so as to slreng- 
then the light, and to prevent any heliolropic curvature of the planls un¬ 
der Observation. 
In these experiments I used seedlings of Ricinus communis, Phaseo- 
lus multiflorus, Cucurbita pepo, and of Zea mais. 
The following may serve as an illustration of the results obtained. 
May 22. Two young plants of Phaseolus multiflorus. 
No. I : placed over potash (bell-jar e'). 
No. 2: placed over water (bell-jar c"). 
May 22 
May 30 
Length 
Breadth 
Length 
j Breadth 
No. 1 
6.8 cm 
— 
8.5 cm 
3.0 cm 
No. 2 
4.8 cm 
— 
6.5 cm 
2.5 cm 
The lenglh includes the petiole — the breadlh could not be measured 
in the first inslance, for the pinnce were still folded together. 
Each plant had also developed a young leaf in addition. 
No. 1 . contained starch in guard-cells of stomata only. 
No. 2. contained starch abundantly in the mesophyll. 
The third series of experiments was made with fully developed plants, 
a single growing branch being iutroduced into an atmosphere conlainiug 
no carbonic acid, whilst the remainder of the plant was in the air 
I he arrangement was siinilar to that described in reference to the ex¬ 
periments with blue light (Fig. 1), but in this case the saucer was filled 
with strong solution of potash, and a simple bell-jar was used instead 
of one with double walls. The freedom of the air front carbonic acid 
was tested, as beforc, by roeans of barvta-water with the sarne results. 
The planls used were Cardiospermum halicacabum. Dolichodeira tubi- 
flora, Helianthus annuus. 
With the first-named plant I obtained the following results, and 
Ihose obtained with the others were quite siinilar. 
The terminal bud of the stem was introduced into the bell-jar over 
potash on June 23., and was removed on June 29. Wilhiu the six dajs 
it had developed three perfectly normal leaves and three tendrils. 
An exaraination for starch shewed that it existed only in the guard- 
