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for Systematic Biology. 
method of work we are referring to will discover its true place 
and receive new life and stimulus from the discovery. This 
particular study does not deal with our series of units as series 
but works within the individual unit, i.e. with its numberless 
reproductions; and it may be that a mathematical study of the 
fine quantitative variations among the representatives of a unit 
may reveal to us the laws which link one unit with the next 
above it and the next below it, or explain the divergence of a 
unit into two or three new ones. We shall only know when we 
can compare its results with those obtained by the comparative 
method. I feel confident, indeed, that all along the line, biological 
study will be both controlled and stimulated to new efforts, and to 
new enquiries, as soon as our systematic work supplies us only with 
facts, and facts arranged ready for further research. For instance, 
as soon as we can leave the ‘ species ’ to take care of themselves 
and have forms as the main objects of systematic work, and 
collect and arrange and study these, observing the surroundings 
in which they are produced to get all the knowledge we can about 
them and about the causes of their differences, we shall, it seems 
to me, be laying the best foundations for the study of evolution 
and of the laws and causes of variation. Without wishing to 
make any rash prophecy, it really seems to me as if the change 
of the unit of classification here advocated by confining the work 
of the systematist strictly to the facts of Nature, would stimulate 
Biology almost as much as it was stimulated a century and a 
half ago by the original adoption of the Linnean system itself. 
But, leaving these ideal advantages to be gained by the system 
advocated on one side, I only wish to emphasise the advance 
which the science of systematic biology must make as soon as we 
have a real instead of an ideal unit of classification. It is evident 
that with a symbol for the designation of each varying form, all 
our systematic work can, from its very first step to its last, be 
made, relatively speaking, exact and, so far as it goes, constructive. 
We shall be simply accumulating the facts out of which definitive 
classifications can be slowly built up. We need establish no more 
hypothetical ‘ species ’ for the perplexing of the next student ; as 
already stated the facts will themselves reveal the true species in 
process of time. And then, but not till then, we shall be able 
as far as I see to name such species in the usual way with the 
Linnean binominal formula. 
It is, then, primarily to this demand for a change in the unit 
of classification for the purposes of work that I wish specially to 
draw attention. The question as to what symbol shall be used 
for the new unit is quite a different one. I have described below 
a system which, with the assistance of my friend Mr Jeffrey Bell, 
I have already elaborated for the purpose of working out the 
