SCIENCE. 
ii 7 
ized beings. Graham, in 1862, drew the sharp line 
which separates colloid from crystalloid matter. “His 
researches have required,” says Maudsley, “ a change 
in our conception of solid matter. Instead of the no- 
tion of inert impenetrable matter, we must substitute the 
idea of matter which in its colloidal state is penetrable, 
exhibits energy, and is widely susceptible to external 
agents. This sort of energy is not a result of chemical ac- 
tion, for colloids are singularly inert in all ordinary chem- 
ical relations, but is a result of its unknown molecular 
constitution ; and the undoubted existence of colloidal 
energy in organic substances, which are usually considered 
inert and called dead, may well warrant the belief of its 
larger and more essential operation in organic matter in 
the state of instability of composition in which it is when 
under the condition of life. Such energy would then suf- 
fice to account for the simple uniform movements of the 
homogeneous substance of which the lowest animal con- 
sists, and the absence of any differentiation of structure is 
a sufficient reason for the absence of any localization of 
any function and of the general uniform reaction to local 
impressions.” Graham himself says: “the colloidal state 
may be looked upon as the probable primary source of the 
force appearing in the phenomena of vitality.” The col- 
loidal condition of the dynamical state of matter ; the crys- 
talloidal the static. The former, which is the rule in the 
organic kingdom of nature, is the exception in the inor- 
ganic. Aluminum and ferric hydrates, silicic acid and a 
few other inorganic substances, exist in the colloid condi- 
tion. From analogy there would seem to be but little 
doubt that the colloid state of these bodies differ from their 
crystalloid state merely in the size of the molecule. In 
other words opal, which is colloid silica, is a polymer of 
quartz. If this theory be true there can be no doubt of the 
vastly greater complexity of a colloidal proteid molecule 
than of a crystalloid one. Now it is a very significant fact, 
in this connection, that not a single organic colloid has 
ever been synthesized. Gelatin, which is one of the best 
examples of a colloid, has a comparatively simple structure. 
And, although Gibbs showed, many years ago, that gelatin 
was probably an amido-derivative of the sugar group, yet 
no inverse process has yet given us this substance. That 
matter in the crystalloid and colloid forms may be chemi- 
cally identical, differing only in the size of its molecule, 
may be quite possible. But it is also possible that the dif- 
ference may be a physical one. To produce the colloid 
state from the crystalloid is by no means beyond the power 
of science. We qualify our previous statement then only 
so far as to say that when the chemist produces a body in 
the colloidal form, having the identical constitution of pro- 
toplasm, there is every reason to believe that it will have 
the properties of protoplasm. 
The important question now arises whether, since the 
protoplasm of animals is identical with that of vegetables, 
and the latter is the food of the former, any protoplasm 
whatever is vitalized by the animal as such. That this iden- 
tity exists would seem satisfactorily established. Though 
the protoplasm of vegetables is enclosed within a cellulose 
bag, it is only a closely imprisoned rhizopod. In the Ni- 
tella, it shows all its characteristic irritability, and from 
Vaucheria it escapes to exhibit all its amoeboid movements. 
Spores swim about by cilia or flagella, and the cell division 
of the one kingdom is the same as that of the other. In 
plants, however, protoplasm seems to be associated with 
chlorophyll, whose function was for a long time supposed 
to be to decompose carbon dioxide under the influence of 
sunlight. But Draper in 1843, showed that this decomposi- 
tion took place before the chlorophyll was formed. Recent 
researches have shown that the function of chlorophyll is 
wholly protective. The assimilative power of the proto- 
plasm reaches its maximum in the orange and yellow rays. 
Now Bert has shown that the absorption band in the chlor- 
ophyll spectrum is in the exact position of this maximum. 
Hence, Gautier believes that this substance acts as a regu- 
lator of plant respiration, the greater or less amount of lu- 
minous energy thus absorbed and transformed, being util- 
ized by the protoplasm and stored up. Growth and cell- 
division, however, are independent of orange light, and 
hence of chlorophyll. In the higher plants, these functions ■ 
are performed by a separate and deep-lying set of cells. 
But in the lower, the same cell discharges both functions, 
assimilation going on in it during the day. and growth 
chiefly at night, Sachs had already proved that the maxi- 
mum growth of plants takes place just before daylight and 
the minimum in the afternoon. This retarding action of 
sunlight upon growth is as curious as it is unexpected. It 
now appears that in orange light plants assimilate — absorb 
carbon dioxide and evolve oxygen — but do not grow- — are 
not heliotropic ; while in blue light they are heliotropic but 
do not give off oxygen. Chlorophyll, however, is not con- 
fined to vegetables ; infusoria, hydras, and certain planarian 
worms are green from the presence of this substance, and 
Geddes has shown that such animals, placed in the sunlight, 
give off" a gas which is more than half oxygen. These cells, 
moreover, contain starch granules. 
A still more striking evidence of this intimate relationship 
has been developed by Darwin, in his researches upon in- 
sectivorous plants. Not only do these plants possess a me- 
chanism for capturing insects, but they secrete a gastric 
juice which digests them. Nageli has shown the presence 
of pepsin in yeast cells, and attention has lately been called 
by Wurtz and others to the juice of the Carica papaya which 
contains a pepsin-like substance capable of peptonizing fibrin 
completely'. Moreover, there is the closest similarity be- 
tween diastase and ptyalin ; and the milk of the cow-tree, 
recently examined by Boussingault and found to resemble 
cream closely in composition, shows the presence of an 
emulsifying agent in the vegetable kingdom analogous to 
pancreatin in the animal. 
Another most curious proof of the indentityof animal and 
vegetable protoplasm has been given by Claude Bernard, 
who has shown that both are alike sensitive to the influence 
of anaesthetics. A sensitive plant exposed to ether no longer 
closed its leaflets when touched. Assimilation and growth, 
as well as germination, are arrested by chloroform. The 
yeast plant when etherized no longer decomposes sugar to 
produce alcohol and carbon dioxide ; while the inversive 
and non-vital ferment still acts to convert the cane-sugar into 
glucose ; precisely as under these circumstances, the dias- 
tasic ferment converts the starch • of the seed into sugar. 
By arresting anresthetically the process by which carbon 
dioxide is absorbed and oxygen evolved, the true respira- 
tory process, being less effected, now appears ; and Schut- 
zenberger has proved that the fresh cells of the yeast plan 
breathe like an aquatic animal. 
It would seem then that the protoplasmic life of animals 
is identical with that of plants ; a certain measure of destruc- 
tive metamorphosis taking place in each, evolving energy 
and producing carbon-dioxide and water. When, however, 
this function is examined quantitatively, its maximum is 
seen to be reached in the animal. While the assimilative 
function characterizes the plant, the destructive function 
distinguishes the animal. Hence it is the function of the 
plant to store up energy, to produce the highly complex 
protoplasm. This, consumed by the animal as his food, 
continues his existence as a living being, the energy gradu- 
ally set free by its successive steps of retrogressive meta- 
morphosis, appearing as the work which he performs. If 
this view be correct, it would follow that every individual 
substance found in the animal — save only those which re- 
sult from degredation — must be found in the plant upon 
which it feeds, and this is the fact. The myosin which 
Kiihne has shown to be the distinctive proteid of muscle, 
Vines has found in the aleuron grains of the lupine and the 
castor oil plant, along with vitellini the special proteid of 
the vitellus. The researches of Weyl & BischofFhave proved 
that gluten is formed in the dough of wheat flour by the ac- 
tion of a ferment upon the globulin-substance or plant-myo- 
sin which it contains, precisely as Hammarsten has shown 
fibrin is produced in the action of a similar ferment upon 
fibrinogen. Not only this ; Hoppe Seyler has extracted 
from maize the identical substance which has been shown 
by Liebriech to be the essential chemical constituent of nerve 
tissue, protagon. 
The evidence then would seem conclusive that, since the 
protoplasm of the animal and the vegetable kingdoms is 
identical, the former in all cases being derived from the 
j latter, the animal as such neither produces nor vitalizes any 
[ protoplasm. Two inferences seem naturally to follow from 
this conclusion : 1st, that all the properties of animal proto- 
plasm, and of the animal organism of which it constitutes 
the essential part, must have a previous existence in the 
