THE INTEGUMENTS AND CLOTHING OF MAMMALIA. 147 



and venous ramifications, the fine capillary terminations of which form, 

 on its surface, a network so minute, so interwoven, that the puncture of the 

 most slender needle is followed by a drop of blood : their numbers 

 baffle the utmost stretch of imagination. To these, predominating in size 

 on the cheeks, is owing the roseate hue of health : they evidently possess 

 a certain independency of action, and are influenced by the emotions of 

 the mind : hence the sudden flush of anger, the pallor of rage, and the 

 blush of shame. Many of these minute capillary tubes admit only the 

 serous portion of the blood, excepting when exercise or mental emotion 

 increases their action : multitudes open, by minute orifices, under the 

 name of exhalants, transmitting a vapory exhalation, which, when con- 

 densed on the surface, is known as perspiration, or sweat. In addi- 

 tion to the exhalants, there are cutaneous follicles, secreting an unctuous 

 fluid, the excretory tubuli of which, also, open on the surface of the skin, 

 piercing through the epidermis. The absorbents, or opening tubes of 

 the lymphatics, are almost as numerous as the blood-vessels ; and the 

 nerves are equally multitudinous. 



The nerves, indeed, seem to form a sort of villous tissue of their own, 

 on the surface of the cutis, which has been described, by Bichat, as the 

 " corps reticulaire," and, by others, is termed the nervous, or papillary 

 tissue. These papillae, which are often of a conical shape, consist of 

 fibres, like the hairs of a pencil ; and they are most distinct and abundant 

 where the sense of touch is most acute. On the palms of the hands, on 

 the tips of the fingers, under the nails, on the tongue, and on the soles 

 of the feet, in Man, they are in vast abundance, close together, and 

 arranged in regular lines, straight or winding : on the snout of the Mole 

 and Hog, and on the naked under-surface at. the extremity of the tail of 

 the Spider Monkey, the Opossum, &c., they are also very discernible. 

 Their existence on the skin of the Cetacea has not been detected. 



Fig. 14T exhibits a section of the corium of the 

 Elephant, shewing it to be composed of an inter- 

 lacement of dense white fibres, of a ligamentous 

 nature, the interstices being occupied by the nervous 

 papillae, and by the vascular tissues concerned in 

 exhalation, absorption, and the secretion of the co- 

 louring and horny materials of the pigment and the 



Corium of Elephaut. CUticle 



The epidermis, or cuticle, consisting of an outer and inner layer, 

 is the external investment : it is thin and transparent, except in certain 

 parts of the body, where it assumes a degree of thickness according 

 to circumstances : on the palms of the hands, and the soles of the feet, 

 for instance, it is much thicker than on the body generally ; and on the 

 palms of hard labourers, especially those who use the spade and the 



