in Natural History. 491 
least liable to vary. His classes and orders are avowedly so 
many assumptions, which practice has shown to be convenient ; 
but when we come to genera, the artificial system falls in with 
the natural, as Linnæus framed their characters upon resem- 
blances founded in nature. 
Now in the natural system this machinery of terms cannot be 
employed in the same manner. It is an ascending series from 
the less to the greater predicate. From genera we proceed up- 
wards to orders, and orders we combine into classes. We be- 
come more and more general in our characters, instead of more 
and more definite. Here indeed we ought not to sacrifice, as in 
the artificial scheme, to convenience; and break up well-defined 
genera and orders because they contain a large number of spe- 
cies. If we find a large genus, for instance, as Erica, agreeing 
in some well-marked characters of structure, form, station, and 
properties, it appears contrary to the.end proposed by the na- 
tural system, to divide and subdivide the species into small 
groups, and to give each of these the same value as is now pos- 
sessed by the whole. This is frittering away characters which 
are essential to the use of a genus, and destroying our power 
over it when we proceed to generalise. The value of generic 
terms consists essentially in the distinct conceptions we have of 
them; but if we go on to multiply them, as is at present the 
fashion, we render it as impossible to circumscribe them, as it is 
to parcel out the colours of the rainbow ; and instead of making 
Natural History familiar and popular, it will require the com- 
pass of a man's life to master the terms we employ. If indeed 
the object be to analyse, division may be very convenient, be- 
cause the inquirer may be otherwise bewildered in the multitude 
of particulars. It does not follow from hence that the student 
of the natural system may not avail himself of subordinate 
groups by whatever characters they may furnish; only the 
giving them equivalent names, and making them co-ordinate, 
is 
