XXV1 HISTORICAL PREFACE. 
and twelfth (the two latter volumes having appeared in 1859) ; others were those con- 
tained in the “* Mexican Boundary Report” which had appeared under Professor Baird’s 
editorship in 1859; about half of them were new. 
I have spoken of the collaboration of Cassin and Lawrence in the production of this 
remarkable treatise. Considering it only as one of a series of reports upon the Pacific 
Railroad Surveys, I should bring into somewhat of association the names of those who 
contributed the ornithological portions of other volumes, as the fourth, sixth, tenth, and 
twelfth, — Dr. C. B. R. Kennerly, Dr. J. S. Newberry, Dr. A. L. Heermann, Dr. J. G. 
Cooper, and Dr. George Suckley. Nor should it be forgotten that numberless other col- 
lectors and contributors, whose specimens are catalogued throughout the volume, brought 
their hands to bear upon the erection of this grand monument. 
But what of the genius of this work ?— for I have not measured my words in speak- 
ing of Wilson and Audubon. Can any work be really great without that mysterious 
quality ? Certainly not. This work is instinct with the genius of the times that saw 
its birth. This work is the spirit of an epoch embodied. 
But here I must pause. My little sketch is brought upon the threshold of contem- 
poraneous history, — to the beginning of the Bairdian period, of the close of which, as 
of the duration of the Bairdian epoch, it is not for me to speak. When the splendid 
achievements of American ornithologists during the past quarter of a century shall be 
seen in historical perspective; when the brilliant possibilities of our near future 
shall have become the realizations of a past; when the glowing names that went before 
shall have fired another generation with a noble zeal, a lofty purpose, and a generous 
emulation — then, perhaps, the thread here dropped may be recovered by another hand. 
Yet a few words of Preface proper to the present work appear to be required. The 
original edition of the “ Key” was published in October, 1872, in an issue of about 
2,200 copies. It was not stereotyped, and has been for some years entirely out of print. 
It formed an imperial octavo of 361 pages, illustrated with 238 woodcuts in the text and 
6 steel plates. It was designed as a manual or text-book of North American Ornithology. 
To meet this design, the Introduction consisted of a general account of the external 
characters of birds, an explanation of the technical terms used in describing them, and 
some exposition of the leading principles of classification and nomenclature. An artificial 
“key” or analysis of the genera, constructed upon a plan found practically useful in 
botany, but seldom applied to zodlogy, was introduced, to enable one who had some 
knowledge of the technical terms to refer a given specimen to its proper genus. Then, 
in the body of the work, each species was briefly described, with indication of its 
geographical distribution and references to several leading authorities. The families and 
orders of North American birds were also characterized, and a synopsis of the fossil birds 
was appended. The work introduced many decided changes in classification and nomen- 
clature which the then state of the science seemed to require, and systematically recog- 
nized a large number of those subspecies or geographical races which are now indicated 
by the use of trinomial nomenclature, — a method now fully established and recognized 
as peculiar to the “ American school.” The central idea of the treatise was to enable one 
