4H 
Lewis and Tuttle. — Osmotic Properties of some 
had gone still farther; the chloroplasts, now definite in outline, were arranged 
at the periphery of the cell. Starch formation around the chloroplast was 
especially evident at this stage (Fig. 4). Material examined on April 
14 revealed the cells in the normal summer condition, the chloroplast 
being entirely masked by the adherent starch granules (Fig. 5). 
Fig. 2. 
Fig. 5. 
Fig. 3. 
Figs. 2-5. Picea canadensis . Fig. 2. Feb. 28. Mesophyll cells after treatment with 1 % osmic 
acid showing vacuoles filled with fats. Fig. 3. Apr. 7. Mesophyll cells treated with iodine solu- 
tion. Chloroplasts becoming distinct in outline although still localized in distribution ; nuclei not 
visible ; starch reaction localized. Fig. 4. Apr. 10. Mesophyll cells in iodine solution. Chloroplasts 
arranged at periphery of cell ; nucleus visible and suspended in central vacuole ; starch formation 
in region of chloroplasts. Fig. 5. Apr. 14. Mesophyll cells treated with iodine solution. Nucleus 
not visible at this stage. Chloroplasts closely packed round periphery of cell and masked by starch 
granules, nu. = nucleus, v. = vacuole, chi. = chlorophyll, ppl. — cytoplasm, st. = starch. 
