68 ANIMAI PHYSIOLOGY 



ridges with furrows between them which characterise those 

 parts. 



43. The sensibility of the skin is due to the presence of 

 nerve terminations, which are of different descriptions and 

 at different depths. The largest of these are termed Pacinian 

 bodies, and are especially found in the subcutaneous adipose 

 tissue of the fingers and toes (fig. 38). They are grape- 

 shaped structures of such size that they can be recognised 

 by the practised dissector with the naked eye as minute 

 grains, being upwards of ^ of an inch in length ; and they 

 consist each of a dilated end of a nerve fibre, with layers 

 of tough nucleated tissue round about. They are not 

 peculiarly integumentary structures, for the site in which 

 above all others they are found easily and abundantly, is 

 the mesentery of the lower bowel of the cat. Within a 

 number of the papillae of the cutis vera smaller bodies are 

 found, termed touch-corpuscles of Wagner (fig. 37). These 

 are of such size, that each one fills the greater part of 

 the papilla in which it is contained : the structure consists 

 of a firm nucleated core, round which the nerve is coiled. 

 Still smaller end-bulbs (of Krause) are found in or beneath 

 the papillae in places where the skin is delicate, as on the 

 lips and over the white of the eye, and appear to resemble 

 the Pacinian bodies in having the nerve ending in the in- 

 terior. Lastly, it is to be noticed that, independently of all 

 these modes of nerve termination, nervous filaments have 

 been found ramifying between the cells of the epidermis, and 

 possibly terminate in individual cells ; and, although this is 

 the most difficult method of nerve-termination to trace, there 

 can be little doubt that it is the most important. 



44, The glands of the skin are of two descriptions, the 

 sudoriparous and the sebaceous. 



The sudoriparous, or sweat glands, are in great numbers 

 all over the body. In the palm of the hand there are as 

 many as 2500 in every square inch of skin, but in the lower 

 limbs and back there have been estimated to be not more 

 than 600 in the square inch. On the palm, particularly 

 when it is warm and slightly moist, the orifices of these 

 glands may be easily seen with a simple pocket lens arranged 

 in a row on every ridge. Each gland consists of a tubule, 



