‘ 
| May 25, 1871] 
NATURE 
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of the two organic kingdoms. As a certain amount of latitude is 
allowed in a first lecture, I will crave your indulgence while I 
direct your attention for a few minutes to a group of forms}which 
_are said to belong to none of these kingdoms, and to form a kind 
_ of Bohemia of their own, 
_ Prof. Ernst Haeckel of Jena, one of the most profoundly learned 
naturalists and one of the most sensible thinkers of the day, 
advocates the separation into a distinct kingdom of an immense 
series of simple organisms, some of which had been hitherto 
regarded as plants and others as animals, 
Prof. Haeckel’s opinion on a matter of this kind is of the 
highest value, not because he has made a bold and certainly 
premature attempt to rearrange the universe on Darwinian prin- 
ciples, but because he has been a most sagacious and careful 
student of the lower forms of life. He has raised for himself a 
monument in his wonderful monograph of the Radiolaria, which 
will endure along with Darwin’s researches on coral reefs and on 
the Cirripeds, when the Darwinian theory of modification through 
Natural Selection may possibly be remembered only as one of 
the most brilliant of those broken lights which have been shed 
from time to time by gifted men on the plan of the Divine 
Creator. 
According to Professor Haeckel, the material universe, so far 
as we at present know it, resolves itself into minerals, protista, 
plants, and animals. I may say at starting that, along with 
most of my brother naturalists in Britain, I regard the introduc- 
tion of this new “kingdom,” the Protista, as a mistake ; but as 
the proposal even involves most interesting questions as to the 
‘relations between the three recognised kingdoms, it is well 
worthy of careful consideration. Haeckel ranges among the 
Protista the Monera, a group of peculiar forms, of which he 
himself has been the most successful student, and these may be 
taken as the type of the ‘‘ Protistenreich ;”” the protoplasta, con- 
taining amceba, difflugia and their allies ; the diatoms, the flagel- 
late infusoria ; the fungi; the noctiluca ; and the rhizopoda. 
It is foreign to my present purpose to trace in detail the various 
steps by which our views of the ultimate process of organisation 
have been modified during the last few years; how after 
the publication of the brilliant observations of Schleiden and 
Schwann, thenucleated cell was almost universally regarded as the 
physiological unit ; how the researches of Max Schultze, Ley- 
dig, Beale, and Hofmeister gradually shook our faith in the 
earlier conceptions of this cell-unit, and did away at all events 
with the necessity of a cell-wall, proving such a wall, when it 
existed, to be an excretion, and showing that the vital activity of 
tue cell resided solely in the nucleated spherule of contractile 
sarcode which forms the cell-contents of every living cell—and 
how finally Cohn, Max Schultze, Huxley, and Haeckel cast 
doubts upon the value of the nucleus and upon the necessity of 
any cell-like limitation, and seemed to render the view highly 
probable that the vital activity of all organisms, even of the most 
highly organised, resides essentially and ultimately in a diffused 
homogeneous ‘‘ germinal matter,” or ‘‘ protoplasm,” of which all 
formed tissues are modifications or excretions. 
It is impossible in the present state of knowledge to subject 
any view as to the ultimate mechanism of the formation of tissue 
through the means of protoplasm to direct proof. It seemsnow 
to be a very generally received opinion, supported by Huxley, 
Max Schultze, Hofmeister, Beale, and many others, and notably 
by Oscar Schmidt, who would seem to bring it almost to 
demonstration in his beautiful researches on the sponges of the 
Adriatic, that protoplasm is simply converted, with a certain 
change of composition, into tissue or ‘formed material.” There 
are, however, almost insuperable objections to this view. The 
secondary products of organisation (formed material) are most 
various in their chemical constitutions, and it involves the admis- 
sion that protoplasm may change in its chemical composition 
till it is @/most carbonate of lime, or silica, or starch, or horn, or 
cellulose ; the last stage of the metamorphosis being its absolute 
separation as one or other of these bodies. Another view which 
I have always regarded as more probable is that protoplasm, the 
substance which is endowed with the peculiar vital property, has 
always the same composition, and that it acts simply by catalysis, 
inducing, under certain known jaws, decomposition and re- 
combination in compounds which are subjected to its influence, 
without itself undergoing any change, absorbing the nascent pro- 
ducts of combination and decomposition, and recombining them 
and reserving them with reference to the development or main- 
tenance of the organ to which it gives its life. 
The researches of Prof, Haeckel on the Monera have perhaps 

been of higher value in support of the protoplasm view than any 
others, for they have given abundant proof that independent 
beings may exist and may show all the essential phenomena of 
life without the slightest trace of differentiation of any part of 
their substance into investing wall or nucleus or distinguishable 
part of any kind, simply as masses of contractile jelly, particles of 
albumin endowed with the faculties of nutrition and reproduction. 
The positive character to which Prof. Haeckel trusts for the 
definition of his protista kingdom is the entire absence in all the 
groups which it contains of sexual reproduction. He contends that 
all protista are monogenetic, reproducing by gemmation or fission 
alone. This character he conceives separates them definitely 
from true animals and true plants. Before passing to the con- 
sideration of the general relations of the animal and vegetable 
kingdoms and the position of these questionable forms, I wish to 
say that I do not attach much importance to this negative 
character. Of late years enormous advances have been made in 
our knowledge of the process of reproduction in lower organisms, 
and we find that multiplication by gemmation in various forms 
is infinitely more common than was supposed; that in some 
cases multitudes of individuals and apparently several generations 
are reproduced by gemmation alone, without the intervention of 
exual reproduction ; but at the same time I believe that the 
tendency of modern research is to make it more and more pro- 
bable that in all cases conjugation or some other form of sexual 
reproduction comes in at some part of a definite or indefinite 
series of broods, and starts as it were an entirely new stock. I 
am inclined to think that in those cases where we find only 
monogeny, it is probably from a want of knowledge of the life 
history, not of an individual, but of a complete cycle of indi- 
viduals. Besides, the reproductive process in some of these 
lower forms is very obscure. Not many years ago, accepting 
Prof. Haeckel’s test, all the orders of cryptogamic plants would 
have belonged to 'the protista. Who could have anticipated the 
obscure and beautiful process of fertilisation in ferns? It seems 
scarcely possible that there should be no equivalent process in 
fungi, if we could only find it out. 
Let us now consider for a moment the characters on which 
the older kingdoms have been founded, and see how they have 
stood the test of advancing knowledge. We shall thus be the 
beter able to judge of the stability or otherwise of the proposed 
new kingdom. 
The consideration of the inorganic kingdom need not, I 
think, detain us long. Any two groups of things conceivable 
must have some analogies or resemblances ; but it seems to me 
that any essential relations which have been founded on 
the resemblances between inorganic substances and organised 
beings are purely fanciful. Of course, it is impossible to say 
that a point of continuity may not be discovered, but as yet the 
boundary line seems sufficiently trenchant. 
Inorganic substances never /ive, they are either simple (accord- 
ing to our present state of knowledge) or they may originate 
from the combination of two or more substances which unite in 
definite proportions ; they may exist in any physical condition 
from solid to gaseous, but they are homogeneous, that is to say, 
any portion which may be detached exactly resembles the re- 
mainder in composition and in properties ; they increase by the 
addition of like particles from without to the external surface ; 
they may be indefinite in external form or amorphous, but 
almost universally they tend to assume the form of regular geo- 
metric solids bounded by planes, which have a definite relation 
to one another in position—to crystallise. Internally inorganic 
substances are at rest, unless their atoms be set in motion, or 
unless they be otherwise affected by forces acting from without ; 
they initiate no motion nor change. If one could imagine a 
quartz crystal absolutely isolated from allexternal influences, it 
might remain unchanged for ever. 
An organised being, on the other hand, either /ves or has 
lived during some part of its existence ; if living, every part of 
it is in constant motion and change ; it increases by the imbibi- 
tion of heterogeneous matter from without, by its assimilation, 
and by the intercalation of the particles of the assimilated food 
among the particles of the substance already laid down, by 
molecular intussusception; and old molecules which have 
undergone change are constantly being removed and replaced 
by new ones. An organised being always contains a mixture 
of solids, liquids, and gases; it is never homogeneous nor 
uniform in structure, but consists of structural elements which 
are distinct in character, and each of which has its part 
to play in the production and regulation of the movements 
