484 THE TISSUES. 



and on the lips. His assertion, also, that the papillae containing 

 axile corpuscles have no vessels, is not confirmed by Kolliker's 



Fig. 323. 



Two papilla from the extremities of the fingers, -without epithelium, and with axile corpuscles (a) 

 and nerves (b). A. Simple papilla with four nerve-fibres and two terminal loops (c). B. Compound 

 papilla with two vascular points with capillary loops (d), and one nervous point with a terminal 

 oop (e). (Kottikcr.) 



observations, though it may apply to particular cases. It is very 

 probable that the nerve-fibres do not in all cases enter into the pa- 

 pilla at all, but terminate in the superficial plexus at their base. 1 



Development of the Skin. 



The corium consists, at first, entirely of cells; among, and from 

 which, subsequently, the white fibres and the elastic tissue, the 

 vessels and nerves are formed. It evidently grows from within 

 outwards, so that the papilla? are developed last of all. It also con- 

 tinues to grow a long time after birth, it being only half as thick 

 in children under seven years of age as in the adult. (Krause.) In 

 embryo of two months, it is 2 iroir to TsW f an inch thick, and 

 presents tolerably distinct collagenous tissue. In the fourth month, 

 the first lobules of fat appear, and the ridges of the hand and the 

 sole of the foot. 



The epithelium of the skin has its first layers developed by the 

 metamorphosis of the most superficial of the primordial cells of the 

 embryo. The outermost layers of these become the cuticle, and 



1 While Kolliker maintains that the nerve-fibres terminate in loops on the sur- 

 face of the axile corpuscle, Meissner regards the cross striae on the latter as the 

 termination of the dark-bordered nerve-fibres. 



