EXPLANATION OF PLATE VIII & VL— continued. 



Figs. 20 — 22. — Mesocarpus scalaris. 



20. Cells a, b, insolated in blue light ; c, non-insolated cell showing 

 tannin-vesicles. Exp. 41. 



21. Cells a, b, c, d, cells insolated in red. Exp. 43. 



22. Isolated tannin-vesicles stained with Millon's reagent. 

 Figs. <i,2>—%&.—Nitella. 



23. Insolated area highly magnified. The small and large cleaf 

 vesicles with one or two peripheral dark needle-points are contents of 

 unknown character. 



24. Insolated area from a terminal leaf-segment, highly magnified. 



25. Portion of insolated and non-insolated area of a cell treated 

 with dilute HCl. 



26. Decolorised chlorophyll-corpuscles, some containing starch. 

 Very highly magnified. 



Figs. 27. — Tradescantia virginica. a, b, stamen hairs ; p, pollen grain. 

 Cells enclosed in dotted line insolated for five minutes. Exp, 48. 



Fig. 28. — Spectra of chlorophyll in a green cell and of the different 

 coloured lights employed compared with the solar spectrum. 



Fig. 29. Schema showing relation of assimilation to respiration in tissues 

 with and without chlorophyll in different intensities of day-brightness : 

 direct sunlight = 100. 



a h, probable assimilation-curve in green tissue without chlorophyll. 

 a g, assimilation-curve of green tissue with chlorophyll, assuming 

 that the colouring matter diminishes the assimilation 20 per cent. 

 c d^ respiration-curve of green tissue without chlorophyll. 

 c/, probable actual respiration-curve of green tissue with cbloro- 

 phyU. 



