SKIN AND ITS APPENDAGES. 127 



ecopic observations, however, seem to regard the rete- 

 mucosum as forming the internal layer of the cuticle, and 

 being the fresh secreted substance from the cutis vera, 

 which gradually hardens into the cuticle as it approaches 

 the surface. Henle has found it to consist of small oval 

 cells, containing a nucleus which became hardened, flat- 

 tened, and ultimately changed into the scales of the cuticle. 



The coloring matter is also found to be produced by 

 cells, called pigment cells each containing a nucleus, and 

 many granules. The choroid coat of the eye, it is said, exhib- 

 its the pigment cells both distinctly and beautifully. The 

 pigmentum iiigruni is sometimes absent in different parts 

 of the body, as in the eyes of Albinos who are thereby very 

 sensitive to light. 



The Cuticle, Epidermis, or Scarf Skin, is the outermost 

 or most external layer of the skin. It is easily separated 

 by blisters, maceration, or putrefaction, and often comes 

 off during scarlet fever; on raising it, it is seen to be con- 

 nected by delicate filaments and hairs to the parts beneath. 

 It consists of one homogeneous layer, destitute of cellu- 

 lar tissue, vessels, and nerves. When separated, it pre- 

 sents the character of the horny tissue is hard, and varies 

 greatly in thickness in different parts, according to press- 

 ure; for example, it is thickest in the palms of the 

 hands and soles of the feet ; it exactly adapts itself to all 

 the inequalities, as the papillae and furrows upon the cutis 

 vera, and from being without nerves and blood vessels, and 

 consequently without sensation and circulation, is admi- 

 rably suited to protect the very delicate and sensitive sur- 

 face of the cutis below. At the mouth, anus, and other 

 natural apertures, it is continuous with the epithelium or 

 cuticle of the mucous membrane. 



Under the microscope, the cuticle consists of several suc- 

 cessions of small, hard, dry laminae or scales, each of which 

 contains opaque spots of the original nucleus and cells, now 

 flattened into scales, of an irregular form, overlapping 

 each other at their edges, and constantly desquamating or 

 falling off like particles of bran. It is nothing more than 



