122 



SPECIAL HISTOLOGY. 



and therefore needs no further description. Elsewhere the papillae are 

 more irregularly scattered, either very close together, as in the labia 

 minora, the clitoris, the penis, and the nipple, or somewhat more widely 

 apart, as upon the extremities, with the exception of the places named, 

 on the scrotum, the neck, chest, abdomen, and back. 



The size of the papillae varies considerably ; the shortest (J$ to 4*0, 

 of a line) occur in the face, especially upon the eyelids, brow, nose, 

 cheeks, and chin, where they are even wholly wanting, or are replaced by 

 a network of depressed ridges ; next upon the female breast (g 1 ^ to g^), 

 upon the scrotum, and at the base of the penis (^ to ^ of a line). In 

 most other situations their length is from -J 2 to -^ of a line. The 

 longest, (33 to 3*3 of a line) exist on the surface of the palm of the 

 hand, sole of the foot, and the nipple, where they are generally of the 

 compound kind ; further, the anterior and posterior extremities of the 

 bed of the nail (y^ to j^), and the labia minora (^ to ^ of a line). 

 The breadth of the base in most of the papillae about equals or is some- 

 what less than the length ; in a few, as in those of the scrotum, prepuce, 

 and root of the penis, it even exceeds the length by J or more, whence 

 these papillae exactly resemble warts, or even short ridges ; in the 

 longest papillae, lastly, the breadth is J to J the length. 



The thickness of the corium varies from J to 1 J of a line, and in most 

 places is about J to f of a line. It is the thinnest (J to J of a line) in 

 the meatus auditorius externus, in the eyelids, the red border of the lip, 

 the glans penis, and clitoridis', and thickest (J to 1 line) on the back, 

 chin, upper and lower lip, (the hairy part), the alee nasi, upon the ball 

 of the sole, the extremity of the great toe, the scapula, and the nates ; 

 on the heel, 1 to 1J lines. 



The principal chemical characters of the corium agree with those of 



the connective tissues, of which it is 

 principally constituted. It putrefies 

 with difficulty, and not at all when 

 tanned; it may be easily dried, 

 and then becomes yellowish, trans- 

 parent, and hard, but flexible and no 

 longer subject to putrefaction. In 

 boiling water, it at first shrinks, 

 eventually however dissolving, but 

 not with equal facility in all animals, 

 and in the young, more quickly than 

 in the old, into gelatine, colla ; and 

 the same change is effected at the 



FIG. 48. Two papillae of the surface of the hand, from a slightly macerated skin ; magni- 

 fied 350 diameters, a, Wavy, remarkably distinct fibrils of connective tissue; b, Transverse 

 elastic fibrils lying in the axis of a papilla and transverse nuclei, axile corpuscles, the corpus- 

 cula tactus of R. Wagner (see 37) ; of nerves no trace is to be seen without reagents. 



Fiar. 48. 



