MITELLASTRA AND RUBACER., 235 
in each. In a word, the character of Bossekta, as Necker really 
gave it, excludes from the genus completely every Rubus known 
at that time save R. odoratus alone. Yet Mr. Rydberg says: 
“There is nothing in Necker’s diagnosis that points directly to 
R. odoratus. It is only by inference that any one may come to 
the conclusion that that species is intended.” The first sen- 
tence of this is already on my list of absolute falsities; nor do 
I think the cause of truth and science can ever demand its re- 
moval thence. But now a word upon the philosophy of that 
delectable phrase, “ only by inference.” 
One side of the moon Mr. Rydberg and I, under favorable con- 
ditions, may see to be a hemisphere. The other side of it 
we shall never see or be able to visibly match with the hemi- 
sphere we do see (as we might match two different specimens of 
Rubacer). Do we know that the moon’s invisible side has a convex 
and not a plane surface? Assuredly we do know it, and 
as certainly, “only by inference.” Do we know that this 
planet whereon we botanize is spherical? Its sphericity no man 
ever saw or will see. We do know it a sphere, but “only by 
inference.” Why have learned men and masterly botanists, 
Linnaeus, Jussieu, Endlicher, Bentham, Gray, and some hun- 
dreds more—why have they published thousands of plant genera 
by diagnosis only, citing not a type? Solely for the convenience 
of those who, competent to use such books, infer to a certainty 
the generic identity of things from those diagnoses alone. Did 
my friend when he published the Auédacer diagnosis not expect 
each possible finder of an unknown species of it, if a botanist, 
to be able to infer to a certainty the genus from his description 
alone? If not, then he wastes time, ink and paper in writing 
diagnoses; for these are then a dumb show; a useless mere for- 
mality. What use in a Gray’s Manual, a Britton’s Manual, a 
De Candolle’s Prodromus, or any of the untold thousands of 
other such books, but through this, that untold thousands of 
educated people, competent to use them, may infer to a certainty 
the genera and the species by the diagnoses alone ? 
This “only an inference’ ‘compels the inference of sorry limi- 
