294 THE AMERICAN NATURALIST.  [VOL. XXXIII, 
the second category stands forth as by far the most important 
sense of the term “ species,’ and much confusion and difficulty 
would have been avoided if it had been consistently restricted 
to that purpose. But equally loose has been the application of 
the subordinate designations “ subspecies,” “ variety,” “form,” 
and “race.” With “amount of difference ” as the only crite- 
rion, fossils, geographic races, and artificially produced varieties 
are being catalogued miscellaneously and indiscriminately as 
“species.” 
After this failure to distinguish between the different tasks 
of taxonomy, it is not surprising that the total difficulties have 
been set forth with as complete an absence of discrimination. 
It is true, for instance, that some so-called species are arbi- 
trary and artificial concepts, though it is equally true that other 
species are clearly defined assemblages of similar individuals, 
the case depending on how we make our terms and how we 
use them. But it is least certain that any method of pro- 
cedure is faulty which tends to obscure the various issues and 
make confusion where none need exist. The limitations of 
our ignorance are already great enough without unnecessarily 
increasing them. A student of geography might conclude, 
after spending some time on the attempt, that it would not be 
worth while for him to write a monograph of the Florida Keys, 
but we would scarcely expect him to advertise his failure by 
composing a treatise to show that geography is an impossibility, 
since coast lines and landmarks are continually changing. The 
facts of nature are what we are trying to learn, not systems 
and concepts. These are, at best, but means, and we should 
change or throw them aside if they fail of their purpose, instead 
of allowing ourselves to become entangled in them. Let the 
term “ species ” be abandoned altogether, if by so doing we can 
better realize that the tasks of biological taxonomy are not one, 
but several, and that each should be.approached to the great- 
est possible advantage without being gratuitously complicated. 
To trace lines of descent and be able to locate each individual 
in its proper place is a work quite distinct in plan and execu- 
tion from the mapping of the islands of life as they lie in the 
sea of nonexistence. The topography of individual islands is 
