SENSE OF TOUCH. 171 



will be apparent when we view it as leather. It is not 

 equally thick in every part of the body ; but, like the cuticle, 

 is most dense in the parts most exposed ; as may be seen in 

 the extremities, particularly over the fetlocks, knees, and 

 hocks ; as well as over the back, belly, and some parts of 

 the head : it is also much more loose and flexible in some 

 parts than in others, to admit of motion. It is connected 

 internally, with the cellular and adipose membranes beneath 

 it ; and wherever it is so connected it is more loose, in pro- 

 portion to the amount of cellular tissue dividing it from the 

 muscular substance : in some parts it is thrown into folds, to 

 admit of instant action, as behind the fore legs. Its outer 

 surface is garnished with numerous papill?e, which are small 

 eminences extremely sensitive, lying under the cuticle, which 

 they secrete in a fluid state ; and wherever the skin is most 

 sensitive, these papillae are found most extensive. The cutis, 

 like the cuticle, is perforated by numerous openings, which 

 are the mouths of ducts. The cutis is elastic, as we know 

 by the effects of pregnancy, in wdiich it becomes greatly 

 distended ; yet soon recovers its former dimensions. The 

 bloodvessels, nerves, and absorbents of the cutis are most 

 abundant. 



SENSE OF TOUCH. 



This sense principally resides in the skin, which is uni- 

 versally affected by many external circumstances, as those 

 of heat and cold, dryness and moisture. But it is by some 

 particular parts, as the lips, that horses attempt particularly 

 to distinguish objects ; and in these it is observed, that 

 the cutaneous nerves are more numerous, and the cuticle 

 much thinner. The irritabihty of the skin is frequently 

 very great : that mixed sensation between pain and pleasure 

 called tickling is an instance of its susceptibility. 



Adipose membrane, or fat, forms a considerable portion of 

 the body of most animals ; but it cannot in the horse be 

 regarded as a complete investment, since many parts are 

 without it, as the eyelids, ears, sheath, and some parts of 

 the extremities. It appears composed of a membrane, so 

 disposed as to form cells, neither the number nor the size 

 of which are the same in all parts of the body. In the 

 mesentery, omentum, and about the kidneys, they are large 



