64 PHARMACEUTICAL BOTANY 
cellular-air-spaces to the mesophyll cells which line these, whence 
it is absorbed. Within the mesophyll cells are found small 
chloroplasts composed of protoplasm and chlorophyll. The 
kinetic energy of the sun’s rays is absorbed by the chlorophyll, 
which renders the energy of the absorbed light effective in break- 
ing up the CO: and H:O into their component elements C, H and 
O, and in rearranging them in such a way as to ultimately form 
sugar. ‘This process is called PHorosynruEsis. The stroma of 
Fic. 35.—Demonstration of the production of starch 
foliage leaves. A, leaf with piece of cork attached whic 
of the sun. 8B, the same leaf decolorized and treated wit 
cork 24 hours later to show that starch was removed fro: 
replenished. The illuminated portion turned blue on 
cation of an abundance of starch. C, the entire leaf 
indicated by letters CHO. (Mottier.) 
in illuminated parts of 
h cut off the direct rays 
h iodine after removal of 
m the shaded spot and not 
addition of iodine, an indi- 
was shaded except the part 
the chloroplast has the power of manufacturing starch from the 
sugar formed within it. 
According to von Baeyer, CO, is split into C and Oy, the C 
being retained, the Oz given off. The nascent C is linked with 
HO to form CH:O (formic-aldehyde); six molecules of this are 
then united to form grape sugar or glucose (CsH1.O,). The 
Baeyer theory, however, has been criticized by Willstatter 
others on the ground that formaldehyde is employed with 
difficulty for the synthesis of carbohydrates and so ¢ 
considered as an intermediate product of carbon dioxid. 
and 
great 
annot be 
€ assimila- 
ie. 
