180 NATURAL SCIENCE [September 
that colourless protoplasm is quite competent to effect the dissocia- 
tion in question (i.e, if such ever actually does come to pass), pro- 
vided always that its forces are sufficiently concentrated and its 
position favourable. It is known that the protoplasm of the chloro- 
phyll bodies is, like that of the nucleus, denser than the cytoplasm, 
and this increase of density is doubtless associated with an aug- 
mentation of vital energy and activity. Then why may not the 
nucleus with all its superior density likewise achieve the decomposi- 
tion of carbon dioxide? Because its composition is utterly different 
from that of the cytoplasm ; its function is to generate not special 
matters, but special motions; it excites the activity of the cytoplasm, 
but is not indispensable for metabolism; it is no part of its business to 
decompose gases or liquids; in fact, according to Preyer and Windt, 
it merely regulates the progress of the assimilation and de-assimila- 
tion of the protoplasm. In this connection it may suffice to merely 
mention the amyloplasts of Schimper, the leucoplasts of Sachs, and 
the free formation of starch without the intervention of chlorophyll, 
or even of leucites demonstrated by Belzung. 
If we profoundly consider the matters herein and just now set 
forth, we can hardly resist the conclusion that chlorophyll, z.e. 
the simple pigmentary substance, is not truly the cause or indis- 
pensable auxiliary of the assimilative energy of the protoplasm of 
the leaf, but rather it is one of the direct and immediate conse- 
quences of the vital activity thereof. Whatever increases and 
heightens the vital activity increases at the same time and pari 
pass the amount of chlorophyll. The peculiar and characteristic 
feature in connection therewith is that it is not really a waste- - 
product, or an excretion in any sense, or a product of de-assimilation ; 
it is a specific consequence of the specific life activity interwoven 
with a protoplasmic substratum, whose molecules dissociate but do 
not degrade. Living protoplasm has an active power of respiration, 
and the greening of etiolated leaves grown in the dark is, when they 
are exposed to light, for and by itself no assimilation process, and it 
takes place without decomposition of carbon dioxide. The pigment 
itself is almost certainly a dark dull blue substance, such as can be iso- 
lated from Gramineae more especially,and the mixture thereof with the 
brilliant and stable yellow carotin, which all leaves contain, affords the 
greenery, and at the same time vivifies and, as it were, burnishes it. 
If Mr Etard’s conclusions that a given species of plant may 
contain several kinds of chlorophyll be provisionally accepted, it is 
indispensable that the term ‘chlorophyll’ should mean not the pure 
pigment only, but the entire waste or excretion ensuing from the 
chemical processes undergone in the protoplasm of the chloroplastids. 
His researches furnish a twofold basis. “It is the chlorophylls,” he 
states, “ that are insoluble in pentane, which tend on splitting up to 
