IN VEGETABLE BIOLOGY. 359 
‘the nucleus can usually be made out; this is more commonly 
seen in M. parvulus, var. angustus, which is the subject of fig. 14 
illustrating this point. 
Here may be mentioned an undetermined species of Ulothriz, 
‚in which the chlorophyll is uniformly applied round the wall, but 
after a few days’ darkness it masses at any part of the cell or 
divides into from 2 to 4 portions, which may be disposed in any 
way in the cell. : 
I have ascertained that bright sunlight is capable of causing 
alterations in the form of chlorophyll bodies, although but few 
opportunities for the study have presented themselves. So far 
as my observations go they show that the same effects are seen 
in high light as in darkness, and that much less time is required for 
their production. Shortening of the Mesocarpus-plate (fig. 20 d), 
and its collection into a ball at the cell’s centre (fig. 20 e), was 
seen after 50 minutes in strong sunlight, a very peculiar effect of 
which is massing of the chlorophyll so as to form a couple of 
lenticular bodies separated from each other by a bridge of colour- 
less granular plasma in which pyrenoids may be discovered 
(fig. 15). Should insolation be continued long enough, it may 
happen that the bridge will be disrupted and the lenses thus 
isolated ; occasionally three lenses are formed, of which one 
remains near the centre of the cell. The chloroplasts of Drapar- 
naldia glomerata condense into aring of uniform calibre (fig. 16 a) 
—a prelude, but not a necessary one, to fragmentation,—which 
takes place just as in darkness; fig. 165 shows a ring at the 
point of breaking ; 16 ¢ and d represent divided portions of the 
Ting, either quite free from each other or connected by a plasma- 
bridge, and rounded off or constricted at places where subdivision 
is destined to ensue. All these figures are from a plant exposed 
to bright October sunlight for four hours; it must be mentioned, 
however, that the chlorophyll of many cells resists the tendency 
of high light to modify its form if only four hours be allowed for 
insolation. 
We are thus justified in concluding that intense light and 
Prolonged darkness act in precisely the same manner upon 
‘chlorophyll bodies. This action makes itself evident as a dis- 
turbance of the equilibrium of the bodies, inasmuch as new centres 
are defined around which a regrouping of the chlorophyll takes 
place; and not only so, but, when comparison is made between 
the figures of Plates XIII. and XIV. representing the normal 
