632 British Association . [September, 
coalesces into a globular body, while the intervening portion of 
the spindle gradually disappears. Instead of the single fusiform 
nucleus whose changes have thus been traced, we have two new 
globular nuclei. The egg now begins to divide along a plane at 
right angles to a line connecting the two nuclei. The division is 
introduced by a constriction of its protoplasm commencing at 
the circumference just within the vitelline membrane, and ex- 
tending towards the centre, divides the whole mass of proto- 
plasm into halves, each including within it one of the new nuclei. 
Each of these two young cells divides in its turn in a direction 
at right angles to the first division-plane, while by continued 
repetition of the same aCt the whole of the protoplasm or yolk 
becomes broken up into a vast multitude of cells, and the uni- 
cellular organism — the egg with which we began our history — 
has become converted into an organism composed of many 
thousands of cells. 
In the greater number of plants the protoplasm of most of 
the cells exposed to sunlight undergoes an important differentia- 
tion, part of it becoming separated from the remainder in the 
form of green granules known as chlorophyll granules. These 
consist of true protoplasm, as the green colouring-matter may 
be extracted, leaving behind the colourless protoplasmic base. 
That chlorophyll is a living substance is sufficiently obvious. 
On the cells which contain it devolves the faculty of decomposing 
carbonic acid. On this depends the assimilation of plants — a 
process externally manifested by the exhalation of oxygen, which 
occurs under the influence of light. This aCtion of chlorophyll 
in bringing about the decomposition of carbonic acid is not, as 
was till recently believed, confined to plants. In the green 
Hydra , and in certain green Planarise, chlorophyll is differenti- 
ated in their protoplasm, and probably always adls here under 
the influence of light exactly as in plants. Geddes has shown 
that these animals contain starch-grains in their tissues — another 
striking point of resemblance between them and plants. A 
further approximation between the two organic kingdoms has 
been shown by the researches of Mr. Darwin and others on car- 
nivorous plants. Naegeli has further proved that the cell of the 
yeast fungus contains peptin, a substance formerly known solely 
as a produdt of the digestion of nitrogenous food of animals. 
Nothing shows more strikingly the identity of the protoplasm 
in plants and animals than the fadt that plants may be placed, 
like animals, under the influence of anaesthetics. Plants while 
under this influence absorb oxygen and exhale carbonic acid, the 
true respiratory function which is ordinarily masked by the pre- 
dominant function of assimilation , which devolves on the green 
cells of plants, and which manifests itself under the influence of 
light in the absorption of carbonic acid and the exhalation of 
oxygen. Hence the respiration of living beings is identical 
whether manifested in the plant or the animal, and the 
