MUCOUS SYSTEM. 241 



to the mucous surface, and it resists the contents of the 

 mucous cavities. 



Q. Will you name an important aspect in which the 

 mucous system deserves here to be considered:' 



tf. It is the constant exposure of the mucous surfaces 

 to foreign bodies and matters; the tissue serves to defend 

 organs from the contact of these bodies; in this office it is 

 to the internal organs what the skin is to the external. 



Organization of the Mucous System. 



Q. What is the mucous chorion ? 



Jl. The layer and papillae of the free surface. 



Q. What is the texture lining the ear? 



ft. Its continuity with the pituitary membrane, its mu- 

 cous discharge, its diseases, its want of fibres, prove it to 

 be mucous tissue. 



Q. Where is the mucous chorion thickest? 



/?. In the gums and palate; it is finest in the sinuses 

 of the face and internal ear. Diseases thicken it very 

 much. 



Q. What is its texture? 



ft. It is soft and thick, like velvet, in the stomach and 

 intestines; as it approaches the external openings, it be- 

 comes denser. The extreme softness of the texture in the 

 internal organs will not allow of the variolous pustule ; 

 these pustules appear on the mucous surface, where its 

 density will support their structure. 



Q. Where is the mucous chorion of the deepest colour? 



Jl. In the stomach, where blood gives it this colour; it 

 is paler in the bladder and rectum. 



Q. What effect have the mucous surfaces on milk? 

 31 



