THE COMMON INTEGUMENTS. 169 



pathetic communication between the outer covering of an 

 animal and the internal parts. The hair is kindly allowed 

 to sympathize with the wants of the body generally, and it 

 grows even thick and curled in some very cold countries. 

 In the Orkneys, the horses retain theii' long hair all the 

 year, and English horses taken there do the same. But 

 with us, as the coat falls off (the mane, tail, and fetlocks, 

 being permanent), so the animal presents a fine short coat 

 in the spring ; which is succeeded by the ample shelter 

 of the winter covering. We have proof there is a sympa- 

 thetic effect between the skin and constitution, from w^hat 

 takes place in horses that are constantly immured in hot 

 stables : in them, the body not needing any increase to 

 the covering, the summer coat either remains ; or, if it be 

 changed, it is for one with the same length of hair. Most 

 stimulating substances have the effect of promoting the 

 change of coat, whether it be heat or physic ; and, aware of 

 this, idle grooms give their horses spice and other stimulants 

 to quicken their moulting. The general growth of hair ap- 

 pears to require considerable powers of the constitution ; 

 thus horses at the time of moulting usually have an increase 

 of pulse, dry mouth, and other shght febrile symptoms. As 

 the hair appears to be a production of the true skin, so, if 

 by any means the skin itself becomes destroyed, the hair is 

 not reproduced ; thus in blisters, when properly applied, the 

 cuticle only is raised : but if the blistering matter act very 

 strongly, and the cutis be destroyed, a permanent baldness 

 is the consequence. 



Hair is a long protruding substance, in structure not un- 

 like to a cane ; being covered externally with a glistening 

 dense material, and being of a spongy interior, having a canal 

 through its centre. It withers as it projects. It is of itself 

 not sensitive, yet it conveys feeling very speedily. The horse 

 has hairs that appear to be of three different kinds, but all 

 are of the same structure. Those that cover the body ; 

 those that hang down fi-om the mane or tail ; and those that 

 are placed about the nose and eyes, all are alike ; all have 

 the same structure externally, and all originate by bulbous 

 vascular extremities, situated beneath the cutis. 



The cuticle is a firm insensible covering to the true skin. 

 The substance of the cuticle is by no means equally thick 



