M. H. V. Mohl on the Structure of ChlorophyU. 421 



I may name CUvia nohilis, as a plant in the leaves of which 

 this form of chloroj)hyll-globules is very beautifully developed, 

 and which is therefore exceedingly well-suited for investigation. 



The chlorophyll-globules of the second kind are frequently 

 larger than those above described ; their diameter amounts, for 

 example in the leaf of Ceratophyllum demersum, to y.jjy of a line. 

 In their interior may be perceived, even in the fresh globules, 

 more distinctly however after the action of water, and still more 

 clearly by the blue colour produced by iodine, one or more starch- 

 grains, which not unfrequently are of such size that the green 

 substance forms only a thin eoat over them ; in many cases, 

 however, the starch forms only a subordinate part of the entire 

 globule, appearing under the form of one or more small nuclei, 

 the diameter of which is only one-half or one-third that of the 

 clilorophyll-globule.. The surface of the entire chlorophyll- 

 globule is smoother than in many of the first kind ; the green 

 substance ordinarily with finer granules. 



The action of water upon these globules is often exceedingly 

 slight, frequently quite imperceptible after a continuance of 

 twenty-four hours. Speaking generally, it is limited to render- 

 ing the outlines of the starch-granules more clearly visible, which 

 seems to arise from a little water making its way between the 

 starch-granule and the green suljstance which forms an envelope 

 around it. The latter remains quite unaltered. When a por- 

 tion of it is accidentally removed from the starch- grain in making 

 the sections, or when the latter is caused to swell up by the 

 application of an acid, so that the green coat is broken through 

 and stripped off, it may be perceived that the green substance 

 possesses sufficient solidity to preserve its original shape and the 

 cavity in which the starch-grain lay ; it is however soft enough 

 to allow of being thrown into coarse folds by lateral pressure. 

 Under these circumstances it presents the characters of a gela- 

 tinous mass not sw'elling perceptibly in water, and, so far as can 

 be seen, coloured green throughout its entire thickness. I never 

 saw vacuoles formed in it. Among the plants I have examined, 

 the internal cells of the leaves of Ceratophyllum demersum are 

 best adapted for the investigation of this form of the chlorophyll- 

 globules. 



I have remarked above that these two forms of chlorophyll- 

 globule very often pass into one another, but it must be noted 

 in regard to this, that divers forms never occur in the same cell, 

 although in different cells of the same plant. Eor example, it is 

 extremely common to meet with chlorophyll-globules belonging 

 to the first kind in form and size, but containing in their inte- 

 rior one or more grains of starch. In proportion to the dimi- 

 nishing size of these starch-grains (and they are often so small 



