PREFACE. ix 



mology ; under the former head, defining such terms as relate to Substance, 

 Resistance, Density, Proportion, Figure, Form, Superficies (under which 

 are introduced Sculpture, Clothing, Color, &c.), Margin, Termination, 

 Incision, Ramification, Division, Direction, Situation, Connection, Arms, 

 &c. ; and under the latter, those that relate to the body and its parts and 

 members, considered in its great subdivisions of Head, Truiik, and 

 Abdomen. In short, they may rest their claim of at least aiming at con- 

 siderable improvement in this department upon the great number of new 

 terms, and alterations of old ones, which they have introduced, — in 

 external Anatomy alone falling little short of 150. If it should be 

 thought by any one that they have made too many changes, they would 

 remind him of the advice of Bergman to Morveau, when reforming the 

 nomenclature of Chemistry, the soundness of which Dugald Stewart has 

 recognized : — " Ne faites grace a aucune denomination impropre. Ceux 

 qui savent dejd, entendront toujours ; ceux qui ne savent pas encore, enten- 

 dront plutot.'^ 



Throughout the whole publication, wherever any fact of importance 

 not depending on their own authority is mentioned, a reference to the 

 source whence it has been derived is generally given ; so that, if the work 

 should have no other value, it will possess that of saving much trouble to 

 future inquirers, by serving as an index to direct them in their researches. 



The Authors are perfectly sensible that, notwithstanding all their care 

 and pains, many imperfections will unavoidably remain in their work. 

 There is no science to which the adage. Dies diem docet, is more strikingly 

 applicable than to Natural History. New discoveries are daily made, and 

 will be made, it is probable, to the end of time ; so that whoever flatters 

 himself that he can produce a perfect work in this department will be 

 miserably disappointed. The utmost that can reasonably be expected 

 from naturalists, is to keep pace with the progress of knowledge ; and this 

 the authors have used their best diligence to accomplish. Every new year 

 since they took the subject in hand, up to the very time when the first 

 sheets were sent to the press, numerous corrections and alterations have 

 suggested themselves ; and thus they are persuaded it would be were they 

 to double the period of delay prescribed by Horace. But Poetry and 

 Natural History are on a different footing ; and though an author can plead 

 little excuse for giving his verses to the world while he sees it possible to 

 polish them to higher excellence, the naturalist, if he wishes to promote 

 the extension of his science, must be content to submit his performances 

 to the public disfigured by numerous imperfections. 



In the introductory letter several of the advantages to be derived from 



