THE CHLOROPHYLL-BODIES. 
49 
parietal, their growth in length and breadth is generally proportional to that of the 
cell-wall and protoplasm in which they lie. But if the growth of the cell is very 
considerable, the growing parietal chlorophyll-granules divide ; this takes place by bi par- 
tition, in a direction at right angles to the longest diameter, into two secondary granules 
usually equal in size. If it contained small starch-grains before the division, these 
arrange themselves round the centres of the newly formed granules. These processes 
are inferred from the increase of the number of granules on the one hand, and from 
the frequent occurrence of constricted hour-glass-shaped forms on the other. After 
this bipartition had been discovered by Nageli in Nitella, Bryopsis, Valonia, and in the 
prothallia of Ferns, it was subsequently noticed in all the families of Cryptogams which 
form chlorophyll ; among Phanerogams also it appears widely distributed ; it was dis- 
covered by Sanio in Peperomia and Ficaria, subsequently by Kny in Ceratophyllum, 
Myriophyllum, Anacharis^ Utricular ia, Sambucus, Impatiens, Sec. In cells of the prothal- 
lium of Osmunda exposed to feeble light and containing but little chlorophyll, Kny 
states that moniliform rows of chlorophyll-granules are produced by repeated bipartition, 
which, like the chains of cells of Nostoc, continue to elongate by intercalary divisions ; 
branching takes place also, in a manner similar to that which occurs in Nostoc, some 
of the chlorophyll-granules increasing in size transversely, and producing branch-rows 
by division. 
(c) With reference to the Internal Structure of the Chlorophyll-bodies, scarcely any- 
thing more can be said than that their outer layer often appears denser, and that the 
proportion of water increases towards the interior, the cohesion decreasing, as is apparent 
from the formation of vacuoles. A differentiation into intersecting layers of different 
density has only been once observed, by Rosanolf, in old chlorophyll-granules of Bryopsis 
plumosa. 
Sect. 7. Crystalloids^. — A portion of the protoplasmic substance of a cell 
sometimes assumes crystal-Hke forms ; bodies are produced which, bounded by plane 
surfaces and sharp edges and angles, possess an illusory resemblance to true crystals, 
even in their behaviour to polarised hght ; but they are essentially distinguished from 
crystals by the action of external influences, and at the same time present significant 
resemblances to organised parts of cells. It is therefore legitimate to distinguish 
them by the term Crystalloids'^ proposed by Nageli. They are usually colourless, 
but sometimes act as vehicles of colouring matters (not green), which may be 
removed from them. Their substance exhibits all the more essential reactions 
of protoplasm, its power of coagulation and of taking up colouring matters, the 
yellow reaction with potash after treatment by nitric acid, as well as that with iodine. 
The solubility of different crystalloids is very different, as is generally the case with 
proteids. They are capable of imbibing water, and swell up enormously under 
the influence of certain solutions \ their outer layer possesses greater power of 
resistance than the inner more watery mass. Those crystalloids which have been 
^ Hartig, Bot. Zeitg. 1856, p. 262. — Radlkofer, Ueber die Krystalle proteinartiger Körper 
pflanzlichen und thierischen Ursprungs, Leipzig 1859. — Maschke, Bot. Zeitg. 1859, p. 409. — Cohn, 
Ueber Proteinkrystalle in den Kartoffeln, in the thirty-seventh Jahresbericht der schlesischen Gesell- 
schaft für Vaterland. Cultur, 1858, Breslau. — Nägeli, Sitzungsberichte der k. bayer. Akademie der 
Wissenschaften, 1862, p. 233. — Cramer, Das Rhodospermin, in the seventh volume of the Viertel- 
jahrsschrift der naturforsch. Gesellschaft in Zürich. — J. Klein, Flora, 1871, No. ii. — Kraus, in 
Jahrb. für wissensch. Bot. vol. VIII. p. 426. 
^ [The term ' crystalloid' is, in another portion of this work, used in a different sense, to express 
any substance capable of crystallisation ; see Book III. Chap. i. Sect, i.] 
E 
