182 GENERAL ANATOMY. 



zootomists and naturalists had also observed it, as well as the 

 analogy subsisting between these two parts of the same mem- 

 brane, in the interval of which all the rest of the body is 

 placed. Bichat has particularly insisted upon this continuity. 

 M. J. B. Wilbrand* has recently given an exposition in detail 

 of the cutaneous or tegumentary system in all its divisions. 

 M. Hebreardt has described the transformation of the skin 

 into mucous membrane and vice versa. 



240. The tegumentary membranes, throughout their whole 

 extent, have common characters, of which it is necessary to 

 speak first, but from their difference of situation, texture and 

 functions, they are divided into two parts, which must, subse- 

 quently, be separately described: these parts are, the mucous 

 membrane and the skin. 



SECTION I. 



OF THE TEGUMENTARY MEMBRANES IN GENERAL. 



241. The teguments, however extensive and numerous 

 they may seem, form one single and same membrane, every 

 where continuous to itself from the external skin, to the bot- 

 tom of the last ramifications of the excretory duct of the most 

 deeply seated gland : this membrane consequently has im mense 

 breadth. Its situation is everywhere external or superficial, 

 inasmuch as it is situated on the surfaces of the body whose 

 limits it forms, and as it is every where in contact with substances 

 foreign to the organization; but one portion only is visible ex- 

 ternally, and envelopes the whole body, while the other part 

 is hidden, and lines the alimentary canal, which traverses the 

 trunk through its whole length, from the mouth to the anus. 

 We may hence easily conceive the figure of the tegumentary 

 membrane, to be that of an envelope, and of a canal which 



* Das, huutsystem in alien seinen verzwergungen, anatomisch, physiol. unit 

 patJiol. dargestellt. Giessen, 1813. 



f Mtm. sur fanalogie qui existe entre le systeme wiiqiieux ft dfrmoide,- 

 Mem. de la Soc. med. TfEmul vol. viii. p. 153. 



