FOLIAGE-LEAVES AND THE CHLOROPHYLL FUNCTION. 531 
of the cylindrical sheath and hooded tip, the more apparent 
deviation is one of size. The thickness is such as to prevent 
crumpling. It is to be noted, moreover, that the development 
of the spathe is usually accomplished before the leaves have 
begun maximal growth under normal conditions. If mature 
leaves were sealed into an apparatus similar to the above, no 
changes were discernible until 15 to 20 days later. At this time, 
the starch and other carbohydrates with which they were richly 
loaded having been used, a shrinkage was noticeable, and the leaf 
was found to be in astate of hunger. On restoration to a normal 
atmosphere before decay had begun, they were restored to a 
normal condition. 
If the bell-jar described above were replaced by one with 
double walls enclosing a solution of potassium bichromate which 
permitted the passage of rays chiefly from the lower end of the 
spectrum, the plants grown in an air free from CO, exhibited a 
complete unfolding of the laminæ, and a total disappearance of 
the angles, in a period corresponding to the normal development 
of the leaf. In the period following the unfolding only a small 
amount of expansion oceurred—a smaller amount than that of 
plants in normal air in similar light. At the end of the period 
of 10 days the lamine were fully unfolded, bright green, and 
were recurved at the edges, but began to exhibit signs of 
deterioration. No marked inerease in size had occurred. 
Under light obtained by use of the double-walled chamber 
filled with ammonia-copper-oxide in normal air, the lamina, by 
aid of the diffuse rays from the lower end of the spectrum, which 
accompanied the blue-violet rays, accomplished a development 
corresponding to that of plants grown in diffuse daylight. 
When grown in this chamber in an air free from CO, for 8 
period of 10 days, the leaves remained in a folded position, were 
light green, and were beginning to exhibit signs of deterioration. 
The two series of experiments last described were not repeated 
a sufficient number of times to confirm the above results, and 
certain disturbances of the apparatus render the results untrust- 
worthy. In all the above experiments an examination of the 
corms was made, showing the presence of a considerable amount 
of starch at the conclusion. 
Effect of Darkness.—In order to cultivate plants in darkness, 
but under otherwise approximately equal conditions, a bottom- 
less chamber of galvanized iron, 15 m. x 1 m. X 1:75 m., was 
