48 
MORPHOLOGY OF THE CELL. 
antheridia of Mosses and Characeae become, at the time of fertilisation, of a 
beautiful red; in ripening fruits {Lycium barbarum, Solanum pseudo-capsicum, &c.), 
the change of colour from green to yellow and red depends also on a similar loss 
of colour of the chlorophyll-granules, accompanied by a breaking up into angular 
forms with two or three points (Kraus, /. <:.). Nearly related to the chlorophyll- 
granules are the vehicles of the yellow colouring materials to which many petals 
owe their colour {e.g. Cucurbita). The occasional blue [Tillandsia amoena) or brown 
and violet bodies {^Orchis Morio) are much further removed from this type, although 
they also have a basis similar to protoplasm, which is tinged by a colouring material, 
in these cases soluble in water. 
(a) The Substance of the Chlorophyll-bodies is, irrespectively of the contents referred 
to, destitute of those fine granules which are so generally distributed through colourless 
motile protoplasm. In spite of their sharply defined form they are very soft and 
greasy when crushed; when they come into contact with pure water, vacuoles are 
formed, which at last burst through the green substance as hyaline bladders. Young 
chlorophyll-granules may thus become converted into delicate bladders, in which the 
starch-grains remain ; old grains have much greater consistence. After extraction of 
the green colouring matter out of true chlorophyll-bodies, e. g. the bands of 
Spirogyra or granules of Allium Cepa, the remaining colourless basis possesses greater 
power of resistance, is coagulated, and shows all the reactions of protoplasm already 
mentioned. 
(b) The Origin of the Chlorophyll-bodies has at present only been directly observed 
in the granular forms ; it can to some extent be compared with the process of free 
cell-formation. Round centres of formation within the protoplasm small portions of 
it collect in defined masses; if the centres of formation are at a considerable dis- 
tance from one another, the chlorophyll-granules become round (as in the hairs 
of Cucurbita)', but if they are large and lie close to one another, they are at 
first polygonal, as if flattened by pressure. The process then resembles the formation 
of numerous small swarm-cells in a single cell of Achlya (Fig. 9, A, p. 13); only that 
in this latter case colourless protoplasm always continues to lie between the green 
portion, as in the parietal chlorophyll of the leaves of Phanerogams. If a mass of 
protoplasm collects round the central nucleus during the formation of chlorophyll, 
the granules are often formed in its neighbourhood ; they may then revolve with the 
protoplasm in the cell, or afterwards assume definite positions. In the filamentous 
Algae with apical growth {e.g. Vaucheria, Bryopsis), they are produced in the colourless 
protoplasm-mass of the growing end of the filament, and then remain closely 
applied to the wall. In ripe spores of Osmunda regalis the chlorophyll surrounds the 
nucleus in the form of amorphous cloudy masses, which, however, separate on germi- 
nation as ovoid granules, at first weakly defined, afterwards more sharply (Kny). In 
those cells of young leaves of Phanerogams which contain chlorophyll (cotyledons 
of the sunflower, primordial leaves of Phaseolus, buds of the tubers of the Jerusalem 
artichoke, &c.) a definite layer of hyaline protoplasm devoid of granules is to be observed, 
close to the cell-wall, in which the chlorophyll-granules are subsequently formed ; here the 
appearance is sometimes presented as if the mass were cut up into polyhedral pieces. 
The formation of the chlorophyll-granules is not always contemporaneous with that 
of its colouring matter ; they may be at first colourless (as in Faucheria or Bryopsis, 
according to Hofmeister) or yellow (in the case of leaves of Monocotyledons or 
Dicotyledons imperfectly exposed to light or in process of development), and be- 
come green at a subsequent period; in the cotyledons of Coniferae the green colour 
appears contemporaneously with their origin even in the dark when the temperature 
is sufficiently high, as also in Ferns. The chlorophyll-granules, after assuming their 
green colour, grow by intussusception to many times their original size; if they are 
