PREFACE TO THE FIRST EDITION. XXlil 
although I endeavoured, as far as possible, to preserve those of my pre- 
decessors; but the numerous subgenera I have established required these 
denominations, for in things so various the memory is not satisfied with 
numerical indications. I have selected them, either for an indication of 
some character, or from the common names which I have latinized, or 
finally, after the example of Linnezus, from the mythological nomencla- 
ture, which are generally agreeable to the ear, and which we are far from 
having exhausted. 
In naming species, however, I would recommend the employment only of 
the substantive of the genus, and the trivial name. The names of the 
subgenera are designed as a mere relief to the memory, when we wish to 
indicate these subdivisions in particular. Otherwise, as the subgenera, 
already very numerous, will, in the end, become greatly multiplied, in 
consequence of having substantives continually to retain, we shall be in 
danger of losing the advantages of that binary nomenclature so happily 
imagined by Linneus. 
It is for the better preservation of it, that 1 have dismembered, as little 
as possible, the genera of that illustrious reformer of science. When- 
ever the subgenera in which I divide them were not to be translated to 
different families, I have left them together under their former generic 
appellation. This was not only due to the memory of Linneus, but it 
was necessary in order to preserve the tradition and mutual understand- 
ing of the naturalists of different countries*. 
This habit, necessarily acquired in the study of natural history, of the 
mental classification of a great number of ideas, is one of the advantages 
of that science which is seldom observed, and which, when it shall have 
been generally introduced into the system of common education, will become, 
perhaps, the principal one. By it the student is exercised in that part of 
logic which is termed method, just as he is by geometry in that of syllo- 
gism, because natural history is the science which requires the most pre- 
cise methods, as geometry is that which demands the most rigorous rea- 
soning. Now this art of method, once well acquired, may be applied, 
with infinite advantage, to studies the most foreign to natural history. 
Every discussion implying a classification of facts, every inquiry which 
demands a distribution of materials, is performed according to the same 
laws; and the young man who had cultivated this science merely for 
* Here the author inserts a page of matter containing an explanation of the 
causes which induced him to direct the employment of several forms of type in the 
body of the work, and also of the classes and other divisions which were to be indi- 
cated by the varieties of the letter. ‘‘ Thus,” he concludes the paragraph, “ will the 
reader be able, at one glance, to distinguish the most important portions in every 
page, and the order of arrangement of every idea, and thus will the printer have se- 
conded the author in all those contrivances which his art is capable of supplying to 
the faculty of the memory.’’—Ene. Ep. 
