66 GENERAL ORNITHOLOGY. 
t 
wrong through the natural fallibility of the mind. The result is, that the “‘ natural classifica- 
tion,” like the elixir of life or the philosopher’s stone, is a goal still distant; and as a matter 
of fact, the present state of the ornithological system is far from being satisfactory. It is 
obvious that birds, or any other objects, may be ‘‘ classified” in numberless ways, — in as 
many ways as are afforded by all their qualities and relations, —to suit particular purposes, or 
to satisfy particular bents of mind. Hence have arisen, in the history of the science, very many 
different schedules of classification ; in fact, nearly evéry leader of ornithology has in his time 
proposed his own ‘‘ system,” and enjoyed a more or less respectable and influential following. 
Systems have been based upon this or that set of characters, and erected from this or that 
preconception in the mind of the systematist. Down to quite recent days, the modifications 
of the external parts of birds, particularly of the bill, feet, wings, and tail, were almost ex- 
clusively employed for purposes of classification; and the mental point of view was, that 
each species of bird was a separate creation, and as much of a fixture in Nature’s museum 
as any specimen in the naturalist’s cabinet. Crops of classifications have been sown in 
the fruitful soil of such blind error, but no lasting harvest has been reaped. The confusion 
thus engendered has brought about the inevitable reaction; and the fashion of the present 
day is decidedly the opposite extreme, — that of counting external features of little conse- 
quence in comparison with anatomical characters. Too much time has been wasted in 
arguing the superiority of each of these characters for the purposes of classification; as if 
a natural classification should not be based upon all points of structure! as if internal and 
external characters were not reciprocal and mutually exponent of each other! But the 
genius of modern taxonomy seems to be so certainly right, — to be tending so surely, even if 
slowly, in the direction of the desired consummation, that all differences of opinion, we may 
hope, soon will be settled, and defect of knowledge,.not perversity of the mind, be the | 
only obstacle left in the way of success. The taxonomic goal is not now to find the way in 
which birds may be most conveniently arranged, described, and catalogued ; but to discover 
their pedigree, and so construct their family-tree. Such a genealogical table, or phylum 
(Gr. pidroy, phulon, tribe, race, stock), as it is called, is rightly considered the only taxonomy 
worthy the name, —the only true or natural classification, In attempting this end, we proceed 
upon the belief that, as explained above, all birds, like all other animals and plants, are 
related to each other genetically, as offspring are to parents; and that to discover their genetic 
relationships is to bring out their true affinities, — in other words, to reconstruct the actual 
taxonomy of Nature. In this view, there can be but one “natural” classification, to the 
perfecting of which all increase in our knowledge of the structure of birds infallibly and inevi- 
tably- tends. The classification now in use, or coming into use, is the result of our best 
endeavors to accomplish this purpose, and represents what approach we have made to this end. 
It is one of the great corollaries of that theorem of Evolution which most naturalists are 
satisfied has been demonstrated. It is necessarily a 
Morphological Classification ; that is, one based solely upon consideration of structure 
or form (uop$7, morphé, form) ; and for the following reasons: Every offspring tends to take 
on precisely the structure or form of its parents, as its natural physical heritage; and the 
principle involved, or the-law of heredity, would, if nothing interfered, keep the descendants 
perfectly true to the physical characters of their progenitors ; they would ‘“ breed true” and be 
exactly alike. But counter influences are incessantly operative, in consequence of constantly 
varying external conditions of environment; the plasticity of organization of all creatures ren- 
dering them more or less susceptible of modification by such means, they become unlike their 
ancestors in various ways and to different degrees. Ona large scale is thus accomplished, by 
natural selection and other natural agencies, just what man does in a small way. in producing 
and maintaining different breeds of domestic animals. Obviously, amidst such ceaselessly 
