CHAPTER II. 



THE HORSE CONSIDERED AS A MACHINE. NECESSITY or UNDERSTANDING ITS CON- 

 STRUCTION. GENERAL PHYSIOLOGICAL AND ANATOMICAL FACTS. ARCHITECTURAL 



PRINCIPLES INVOLVED IN THE CONSTRUCTION OF THE SKELETON OF THE JOINTS. 



- THE VERTEBRA. THE CARTILAGES AND LIGAMENTS. THE MUSCLES, VOLUN- 

 TARY AND INVOLUNTARY. GENERAL FACTS, ANATOMICAL, PHYSIOLOGICAL, AND 

 MECHANICAL, REGARDING THE MUSCLES. ARTICULAR LIGAMENTS. TENDONS. 

 THE LAW OF REPAIR IN MUSCLES AND TENDONS. RELATION OF THE FORM OF 

 ORGANS TO THEIR FUNCTIONS. UTILITY MADE TO CONFORM TO BEAUTY IN THE 

 FORM OF ORGANIZED BEINGS. 



IT is proposed to present as concise a view of the locomotive 

 organs of the horse as may be consistent with a proper knowledge of 

 the parts, and the functions they perform in progressive motion. 



There can be no just appreciation of the qualities of a complicated 

 machine without a comprehensive understanding of its construction, 

 and the manner in which each of its parts acts to produce the com- 

 pound movement for which it was designed. So, in order to under- 

 stand the paces of the horse, we must understand the action of all 

 the parts of the machinery by which they are produced. It need 

 not be said that it is very complex, and has never been understood, 

 for the reason that the motions themselves have been altogether mis- 

 interpreted. 



This study of the mechanism of the horse is a necessity which will 

 become apparent to any one who undertakes to analyze these move- 

 ments by the aid of any manual of anatomy yet published. The dis- 

 tinction of muscles into adductors, abductors, extensors, and flexors 

 gives a very inadequate idea, and sometimes a very erroneous one, of 

 the action of the muscles to which those terms are applied, as well as 

 to their general agency in locomotion. In fact, these terms are used 

 to express the action abstractly with reference to the bones to which 



