XXVI FLOIIA OF TASMANIA. 
fication, is sw;i !!..,■ v,! m;> in the gigantic conception of a power intermittently exorcised in the develop- 
ment, out of inorganic elements, of organisms the most bulky and complex as well a < the most niiuute 
and simple; and the consanguinity of each new being to its pre-existent nearest ally, is a barren fact, 
of no scientific significance or further importance to the naturalist than that it enables him to clas- 
sify. The realization of this conception is of course impossible; the boldest speculator cannot realize 
the idea of a highly organized plant or animal starting into life within an area that has been the field 
of his own exact observation* and research ; whilst the more cautious advocate hesitates about ad- 
mitting the origin of the simplest organism under such circumstances, because it compels his sub- 
scribing to the doctrine of the "spontaneous generation" of living beings of every degree of com- 
plexity in structure and refinement of organization. 
On the other hand, the advocate of creation by variation may have to stretch his imagination to 
account for such gaps in a homogeneous system as will resolve its members into genera, classes, and 
orders ; but in doing so he is only expanding the principle which both theorists allow to have operated 
iu the resolution of some groups of individuals into varieties : and if, as I have endeavoured to show, 
all those attributes of organic life which are involved in the study of classification, representation, and 
distribution, and which are barren facts under the theory of special creations, may receive a rational 
explanation under another theory, it is to this latter that the naturalist should look for the means of 
penetrating the mystery which envelopes the history of species, holding himself ready to lay it down 
when it shall prove as useless for the further advance of science, as the long serviceable theory of 
special creations, founded on genetic resemblance, now appears to me to be. 
The arguments deduced from genetic resemblance being (in the present state of science), as far 
as I can discover, exhausted, I have felt it my duty to re-examine the phenomena of variation in 
reference to the origin of existing species ; these phenomena I have long studied independently of 
this question, and when treating either of whole Floras or of species, I have made it my constant aim 
to demonstrate how much more important and prevalent this element of variability is than is usually 
admitted, as also how deep it lies beneath the foundations of all our facts and reasonings concerning 
classification and distribution. I have hitherto endeavoured to keep my ideas upon variation in sub- 
jection to the hypothesis of species being immutable, both because a due regard to that theory checks 
any tendency to careless observation of minute facts, and because the opposite one is apt to lead 
to a precipitate conclusion that slight differences have no significance; whereas, though not of 
specific importance, they may be of high structural and physiological value, and hence reveal affi- 
nities that might otherwise escape us. I have already stated how greatly I am indebted to Mr. 
Darwin' sf rationale of the phenomena of variation and natural selection in the production of species ; 
and though it does not positively establish the doctrine of creation by variation, I expect that 
every additional fact and observation relating to species will gain great additional value from being 
viewed in reference to it, and that it will materially assist in developing the principles of classification 
and distribution. 
* It is a curious fact (illustrative of a well-known tendency of the mind), that the few writers who have in ima- 
11 v. i .n endeavoured to push the doctrine of special creations to a logical issue, either place the scene of the creative 
effort in some unknown, distant, or isolated corner of the globe, removed far beyond the ken of scientific observation, 
or suppose it to have been enacted at a period when the physical conditions of the globe differed both in degree and 
kind from what now obtain; thus in both cases arguing ad ignotum ah ignoto. 
f In this Essay I refer to the brief abstract only (Linn. Journ.) of my friend's views, not to his work now in 
tbt! l™ 3 ' a • ! - U1 >^ i ' stuclj of which nun mo«lit\ .m opinion on some points whereon we differ. Matured conclu- 
