ELEMENTS OF ANATOMY. 



INTRODUCTION. 



Object of Anatomy. — The object of Anatomy, in its most extended 

 sense, is to ascertain and make known the Structure of Organised Bodies. 

 But the science is divided into departments according to its subjects ; 

 such as, Human Anatoni}', in which, as in the present work, the struc- 

 ture of man forms the principal subject ; Comparative Anatomy, com- 

 prehending, as a whole or in various subdivisions, the study of the 

 structure of different animals ; and Vegetable Anatomy, comprehending 

 the investigation of the structure of plants. 



Organs and Textures. — On examining the structure of an organised 

 body, we find that it is made up of members or organs, through means 

 of which its functions are executed, such as the root, stem and leaves of 

 a plant, and the heart, brain, stomach, and limbs of an animal ; and 

 farther, that these organs are themselves made up of certain constituent 

 materials named tissues or textures, as the cellular, woody, and vascular 

 tissues of the vegetable, or the osseous, muscular, connective, vascular, 

 nervous, and other textures, which form the animal organs. 



Most of the textures occur in more than one organ, and some of them 

 indeed, as the connective and vascular, in nearly all, so that a multitude 

 of organs, and these greatly diversified, are constructed out of a small 

 number of constituent tissues, just as many different words are formed 

 by the varied combination of a few letters ; and parts of the body, 

 differing widely in form, construction, and uses, may agree in the 

 nature of their component materials. Again, as the same texture 

 possesses the same essential characters in whatever organ or region it is 

 found, it is obvious that the structure and properties of each tissue 

 may be made the subject of investigation apart from the organs 

 into whose formation it enters. 



General and Descriptive Anatomy. — The foregoing considerations 

 naturally point out to the anatomist a twofold line of study, and have 

 led to the subdivision of anatomy into two branches, the one of which 

 treats of the nature and general properties of the component textures of 

 the body ; the other treats of its several organs, members, and regions, 

 describing the outward form and internal structure of the parts, their 

 relative situation and mutual connection, and the successive conditions 

 which they present in the progress of their formation or development. 

 The former is usually named " General " Anatomy, or " Histology " ;* 

 the latter " Descriptive" or " Special " Anatomy. 



* From IcTThs, a weli. 



