50 THE EXTERIOR OF THE HORSE. 



heavy transportation, in the retail deliveries of large stores, for hack- 

 ney cabs and coaches, which, in a word, are used for all the special 

 requirements, so numerous and so various, of the ordinary city and 

 country life. 



The very diversity of these requirements renders impossible a 

 detailed classification of the horses thus employed. As a general 

 rule, they are used either at a walk or at a trot. In the first case, 

 of course, the burden is always considerable as compared with that 

 in the second. The conformation must therefore be proportionally 

 different. 



This fact permits us to establish two large divisions in this category : 

 heavy-draught horses and light-draught horses. But among heavy- 

 draught subjects there are some whose work is alternately accomplished 

 at a walk or at a trot, and which resemble very much the slow heavy- 

 draught variety by their large- size and the bulk of the weight which 

 they carry, but are distinguished from the light-draught horses by 

 an inferior speed and less slender forms. We have previously given 

 them the name fast heavy-draught horses (see page 409). 



Such are the three tolerably well-defined groups into which horses 

 of service, properly so called, may be divided. Difficulties arise as 

 soon as we undertake to establish secondary divisions. The reason of 

 this is that the three principal factors of the general form, height, 

 bulk, and the gaits, vary only within scarcely appreciable limits, 

 according to the destinations. 



It is less the whole conformation than the education imparted with 

 a view to the adaptation desired which principally specializes a partic- 

 ular aptitude in a given category, like that of the heavy-draught, for 

 example. 



Thus, the shaft-horse, the heavy cart-horse, the tow-horse, the dray- 

 horse, the horse that unloads wood upon the wharf, the horse that is 

 employed to hold the cart back when going down a descent, or to help 

 to draw it when going up a sharp incline, all these are draught-horses 

 that are recognizable as such at first sight, but which education, train- 

 ing, and habit have rendered peculiarly fit for some special service. No 

 doubt the qualities which make special motors of them imply some physi- 

 cal modifications ; but these are imperceptible, owing to the part played 

 by the moral modifications. Now, we must be careful not to confound, 

 among these changes in the form of the body, those which result from 

 actual adaptation and those which proceed from usage. The first are 

 incomparably weaker than the second, and cannot be considered as 

 capable of realizing distinct types of conformation unless these changes 



