,; 



BOOK J. 

 LOCOMOTORY APPARATUS. 



TUK locomotory apparatus is composed of all those organs which ministn ti- 

 the movements an animal may execute. It is certainly one of the most im- 

 portant in the economy, from the number and volume of the pieces whirl i 

 enter into its formation, and by the necessary co-operation that it affords the 

 other apparatus in the performance of the physiological acts which are 

 allotted to them. 



It is constituted of two kinds of organs ; the bones and muscles. The 

 bones, hard and resisting, stony in appearance, are real inert levers, joined to 

 each other by firm and movable articulations, which permit their playing 

 upon eacli other with the greatest facility, at the same time maintaining 

 them in their relative positions. The muscles, grouped around the bones 

 and attached to them, are soft organs which possess the property of contrac- 

 tion, under certain determinate conditions, and of involving in that move- 

 ment the bones to which they are fixed by their extremities. The first are 

 altogether passive in their motion, while the second are really the active 

 organs of locomotion the powers intended to move the bony levers. 



We will treat successively of: 



1. The study of the bones, a particular branch of descriptive anatomy 



which has received the name of osteology ; 



2. The study of the articulations, or arthrology ; 



3. The study of the muscles, or myology. 



FIRST SECTION. 

 THE BONES. 



CHAPTEE I. 



THE BONES IN GENERAL. 



BONES, properly speaking, are only to be found in vertebrate nnimals, and 

 constitute their principal zoological character. In the animal body they 

 form an internal framework which consolidates the entire nlificc, and gives 

 it its general form and dimensions. It is advantageous, before commencing 

 a particular description of each bone, to survey them in a general manner. 

 This study comprises : 1, The description of the skeleton ; 2, The summary 

 indication of the general principles which should bo known in order to com- 

 prehend the details of the special descriptions. 



