BINARY SYSTEMS. 193 
(250.) Binary or dichotomous systems, although re- 
gulated by a principle, are among the most artificial 
arrangements that have been ever invented. This great 
principle upen which the advocates of such tables insist, 
simply consists in arranging animals according to their 
positive and negative characters; as, forinstance, birds with 
perfect wings, and, secondly, birds with imperfect wings ; 
and so on. Now this mode of arrangement is, perhaps, 
the most simple, and the most easy of comprehension, 
of any that has been devised ; and was, therefore, the 
earliest in use. It likewise seems to offer a ready clue 
to the discovery of any particular species or genus, be- 
cause the student has no occasion to look beyond the 
table before him: he need not trouble himself about 
affinities or analogies, for he has merely to see what 
particular character his specimen has, and what it has not. 
When, therefore, his object is either to ascertain the 
recorded name of a species, or whether it be described 
or undescribed, he will often find this sort of catalogue 
useful. But the misfortune of the binary methods of 
arrangement is this, that they may be multiplied ad 
libitum. As their advocates profess not to pursue any 
one principle in the selection of their characters, it fol- 
lows that we may have a hundred different binary sys- 
tems, each good in its way, but each different from the 
other. One entomologist may choose to divide all in- 
sects into such as have wings, and, secondly, such as 
have none. Another, looking to the manner of feeding, 
may make his two groups depend upon one having jaws, 
the other none. A third, considering metamorphosis 
as the corner-stone of his system, may divide all insects 
into such as undergo this transformation, and such as 
do not. Hence, it follows, that every one may form a 
binary system of his own, provided he closely attends 
to, and ‘* possesses distinct conceptions on, positive and 
negative characters ;” the only requisite, as its advocates 
affirm, for this mode of arrangement. As for preserving 
the natural affinities of groups, it is by no means ne- 
cessary to the systems in question that any regard should 
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