COMPARATIVE anatomy, is the sci ence which examines the structure of the-body in animals. It includes, in its most extensive sense, a view of the cor poreal organization of all classes of the animal kingdom.
This science, which is very aptly denominated comparative anatomy, af fords the most essential aid in elucidat ing the structure of the human body, and in explaining the doctrines of phy siology.
The want of any organ in certain classes of animals, or its existence under different modifications of form, structure, &c. cannot fail to suggest most interest ing conclusions concerning the office of the same part to the human subject. Thus our physiological reasonings, which must necessarily be partial and incom plete, when deduced from the structure of a single animal or class, are extended and corrected by this general compara tive survey, and may therefore be relied on with the greater confidence. We are indebted to such investigations for the dis covery of the circulation and of the lym phatic system ; for the elucidation of the functions of digestion and generation ; indeed, there is no branch of anatomy or physiology, which has not received most material benefit from the same source. Hence Haller has very justly observed, that " physiology has been more illustrated by comparative anato my, than by the dissection of the human body." The study of comparative anatomy is moreover of the greatest importance in its connection with veterinary science, and with that highly interesting pursuit, na tural history. It would be" an affront to our readers to enlarge upon its utility in the former point of view ; but we may be allowed to observe on the latter sub ject, that anatomical structure forms the only sure basis of a natural classification of the animal kingdom ; and' that any ar rangement, not founded on this ground work, will lead us into the most gross and palpable errors.
Lastly, this study opens to the mind a great source of interest and satisfaction, in exhibiting such numerous and unde niable proofs of the exertion of contri vance and design in the animal struc ture; in displaying those modifications of particular parts and organs, by which they are adapted to the peculiar circum stances of the animal, and become sub servient to its wants, its necessities, or its enjoyments.
The importance of the subject, from the above-mentioned circumstances, is now so fully recognised, that it begins with justice to be considered as an essen tial part of a regular medical education. Public lectures have been delivered on it for some years in Germany and France ; and lately the example has been followed in this metropolis.
Hitherto there has been rather a defi ciency of good works on this science, and particularly of elementary books. Blasius has given a collection of the writ ings of several authors on the anatomy of particular animals, in one volume 4to., • entitled " Anatomia animalium figuris variis illustrata," Amstel. 1681; which may still be consulted with advantage, particularly on account of the plates. Cuvier's "Lecons d'Anatomie comparee," in five large 8vo. volumes, form a very valuable and useful repository of facts in comparative anatomy ; but the subject is treated at such length, and with so many uninteresting details, that the book is by no means adapted for the use of students. The only compendious and scientific view of the subject, which we can recom mend to beginners, is the short system published by Blumenbach of Gottingen, and translated from the German by Mr. Lawrence, who has accompanied it with numerous additional notes.
The necessity of confining this arti cle. within a given number of pages renders it impossible for us to give a general view of the subject; we shall, therefore, select such parts as are either particularly interesting in them selves, or such as become important from elucidating the structure or functions of the human body.
It is necessary for us. to Make a few remarks on the classification of the ant. mal kingdom, as the terms employed in the following article differ occasionally from those of the Linnxiin system, which has been hitherto chiefly used in this country ; and, independently of this cir cumstance, such of our readers, as have not particularly attended to the study of natural history, may derive assistance and information from a short sketch and ex planation of the arrangement of animals according to their anatomical structure, with an enumeration of the chief genera in each order.