PRACTICAL HISTOLOGY. 



[xxix. 



Stratum 

 corneum. 



(c.) The cutis vera. The papillae, conical elevations projecting 

 into the Malpighian layer. Tliey consist of compact fibrous tissue. 

 The rest of the skin consists of bundles of white fibrous tissue 

 interwoven with networks of elastic fibres, and at its lower part 

 masses of fat-cells. The connective tissue and fat-cells below 

 become continuous with the subcutaneous tissue, which is of a 

 more open texture ; but there is a gradual transition from the one 



to the other. The nuclei of the 

 connective tissue corpuscles appear 

 as red oval dots. 



In sections of the sudoriferous 

 glands, their coils (in the deeper 

 layers of the corium), their ducts 

 running vertically through the 

 skin, and a corkscrew passage in 

 the epidermis may be seen. In 

 some of the papillae observe a 

 touch-corpuscle (p. 320), and in 

 the subcutaneous tissue occasion- 

 ally sections of Pacinian bodies 

 (p. 320). 



(<#.) (H) Observe in the epi- 

 dermis the shape and characters 

 of the successive layers of epi- 

 thelium. In the Malpighian 

 layers, "prickle-cells," i.e., cells 

 connected with each other by 

 fine "inter-cellular bridges," are 

 better studied in an osmic acid 

 section (fig. 97). (See also 

 Lesson IV.) 



(i. ) In the stratum Malpicjliii 

 the lowest cells are arranged in 

 a single layer of elongated, some- 



w i. ni - Pn l lirnTinT , r( A\~ If. T<7 ,.\ 

 W J iat C ells V " 12 J*/ 



with large OVal nuclei SlUTOlinded 



by granular protoplasm. The 

 lower ends of the cells frequently exhibit processes which fit into 

 the derm is. The remainder of the cells of this layer are irregularly 

 cubical, and exhibit prickles (Lesson IV., and p. 127). In the dark 

 races the particles of melanin, which give the dark colour to the 

 skin, are present in the cells of this layer, especially in the deepest 

 layer of cells. Nuclei are sometimes seen in process of division. 



(ii.) The cells of the stratum yranulosum are arranged in two or 

 more layers, and are flattened horizontally, so that they are lozenge- 



FlG. 307. V.S. Human Epidermis with 

 Terminations of Nerve - Fibrils. n. 

 Nerve; d. Dennis; 6. Branches of 



