PROTOPLASM AND NUCLEUS. 
45 
or mass of protoplasm which is connected with the parietal protoplasm-sac by the 
lamellae lying between the vacuoles or by the threads. The nucleus apparently follows 
passively the movements of the protoplasm in which it is enveloped ; it also undergoes 
changes of form under the pressure and traction of the moving mass beneath the 
eye of the observer. 'During the movement,' says Hanstein (/. c, p. 226), 'the 
bands of protoplasm are very tightly stretched, so that the envelope of the nucleus is 
drawn out into sharp angles. It looks as if the nucleus (with its envelope) were 
towed about like a ferry-boat by ropes. But since during this towing the bands 
alter their direction and form, it is evident that the envelope of the nucleus must 
also change its form. But not only the envelope, but also the nucleus itself, does 
this; this latter is never spherical or of any regular form during its movement, but is 
irregularly elongated, and usually in the direction of its motion at the time.' This 
change in the form of the nucleus may also be recognised from the displacement of 
the nucleoli within its mass. 
Sect. 6. The Chlorophyll-bodies and similar Protoplasmic Structures \ 
— Chlorophyll, the green colouring matter so generally distributed through the 
vegetable kingdom, is always united to definite portions of the protoplasm-mass 
of the cells in which it is found ; these green-coloured portions of protoplasm 
may, in contradistinction to the colouring matter itself by which they are tinged, be 
designated Chlorophyll-bodies. Every chlorophyll-body consists then of at least 
two substances, the colouring matter and its protoplasmic vehicle ; if the former 
is removed by alcohol, ether, chloroform, benzin, or essential or fatty oils, the latter 
remains behind colourless. The colouring matter contained in each chlorophyll- 
body is itself only extremely small in quantity ; after its removal the protoplasmic 
basis retains not only its form but also its previous volume. The latter is always a 
continuous soft substance containing extremely small vacuoles, in which the colouring 
matter is generally distributed universally, though not always uniformly. 
Chlorophyll-bodies arise in the young cells by the separation of the pro- 
toplasm into portions which remain colourless and others which become green and 
sharply defined. This may be due to very small particles of a somewhat different 
nature either originally existing or being produced in the previously homogeneous 
protoplasm, and which collect to form distinct masses. The chlorophyll-bodies 
which arise in this manner always remain imbedded in the colourless protoplasm 
in a similar manner to the nucleus ; they are never in immediate contact with 
the cell- sap. Their chemical and physical properties distinctly show that their 
colourless basis is a substance altogether similar to protoplasm. The chlorophyll- 
bodies consequently always behave as integral parts of the protoplasm ; and this 
is especially evident in the division of cells, conjugation, the formation of swarm- 
cells, &c. But the chlorophyll-bodies, when once formed, grow; and if they 
possess roundish forms they may increase by division. Both processes appear always 
to depend on the growth of the protoplasm-mass in which they are imbedded. 
' H. von Mohl, Bot. Zeitg. nos. 6 and 7, 1855; [Ann. des Sei. Nat. vol. VI, 1856, p. 139] 
— A. Giis, Ann. des Sei. Nat. 4th Sen vol. VII. 1857, p. 179. — Saehs, Flora, 1862, p. 129; 
1863, p. 193. Saehs, Handbuch der Exper. Physiol, der Pflanzen, § 87, Leipzig 1865. — Hofmeister, 
Die Lehre von der Pflanzenzelle, § 41, Leipzig 1867.— Kraus, Jahrb. für wissensch. Bot. VIII. 
1871, p. 13T. [Ditto, Zur Kenntniss der Chlorophyllfarbstoffe u. ihrer Verwandten. Stuttgart 1872. 
—For Sorby's researches on chlorophyll see Book II. chap. 3. sect. 8.] 
