GEOOMING. 69 



hair-root is enclosed in a distinct sack of its own called a follicle. The 

 base of the sack is supplied with blood-vessels, from which the materials 

 for the formation of the hair are secreted. The manner of the growth of 

 the hair is similar to that of the outer skin, namely, by cells. The cells 

 are pushed up by new cells forming below. They gradually become 

 flattened and elongated into fibres to form the central shaft of the hair, 

 whilst the outer part is covered by flattened cells or scales overlapping 

 each other like slates on the roof of a house. The cells are cemented 

 together by adhesive matter, which is secreted as they grow. 



104. Shedding of the coat. 



Twice in the year, namely, in spring and autumn, the horse sheds his 

 coat. At those seasons the nourishment of the old hair is arrested, the 

 soft pulpy extremities shrink and dry up, and the hair becomes detached 

 and falls off ; whilst at the same time a new hair is formed and pushed 

 up by its side. 



In autumn longer hairs are supplied as a protection against the cold of 

 winter. In spring these long hairs are cast off, and shorter ones are 

 supplied for summer use. It is not very evident why nature every year 

 goes through this double course of shedding hair in the horse, when the 

 same object might apparently have been attained by an increased growth 

 of the summer coat at the beginning of winter. 



Probably, in order to admit of longer growth, the hairs of the mane 

 and tail are not shed. Their roots are situated more deeply in the sub- 

 cutaneous tissue. 



105. The WJiiskers. 



The whiskers have a similar origin to the hairs of the mane and tail ; 

 but being supplied for the purpose of protection they are made stiff, so 

 that whatever is felt at the tip may also be felt at the root. Into the 

 root of each whisker-hair runs the nerve, which supplies it with its 

 delicate power of sensation. 



It is the fashion of the day to trim off these whisker-hairs ; but it is 

 wrong on principle, though probably the loss is of no great consequence 

 to the domesticated horse. 



106. Objects gained by grooming. 



Grooming answers two principal and several subsidiary ends. First, 

 it removes from the skin those particles of perspiration, dust, and dirt 

 which otherwise would impede and clog the free action of the sweat and 

 oil glands. Secondly, it removes the scurf or worn-out cells which are 

 no longer required on the surface of the skin, and which would, especially 

 when cemented together by particles of sweat, add to the obstruction of 

 the glands. The subsidiary uses of grooming will be adverted to here- 

 after. 



