498 THE INTESTINAL CANAL, BY E. KLEIN AND E. VERSON. 



tissue fibres, between which isolated or plexiform fibres of 

 elastic tissue run. 



The surface of the cutis directed towards the epidermis pre- 

 sents rows of cylindrical or conical small vascular papillse stand- 

 ing in tolerably close proximity with one another, and project- 

 ing into the rete mucosum to about half its thickness. The 

 nervous and vascular trunks proceeding from the subcutaneous 

 tissue, or from the muco-membranous and transitional portions, 

 .make .their way between the muscular fasciculi, and curve at 

 nearly right angles in the cutis. Hairs and sebaceous follicles 

 are distributed in moderate number at nearly equal distances, 

 and at various depths in the tissue. The hair follicles of the 

 upper lip are directed obliquely downwards at their base, those 

 of the lower lip upwards. The points of distinction between 

 the transitional and the cutaneous portions of the lips are the 

 absence of hair follicles and sebaceous glands in the former ; the 

 presence of wedge-like fasciculi of the orbicularis oris in it, 

 which reach nearly to the epithelium ; the much greater trans- 

 parency of its superficial cells ; the arrangement of its morpho- 

 logical elements generally; and, lastly, its far more abundant 

 supply of bloodvessels. 



The epithelium, as a whole, remains at a short distance 

 from the last hair follicles, as deep as at the cutaneous portion, 

 but beyond this rapidly increases in thickness. The super- 

 ficial cells are much flattened, intimately fused with one 

 another, and without apparent nuclei; but those which are 

 rather deeper, though still tabular, become somewhat elon- 

 gated, and possess a well-defined and usually elongated 

 nucleus. The cells of the middle layers increase as they are 

 more deeply situated in their vertical diameter, and become 

 proportionately narrower, with round nuclei ; the deepest cells 

 are round, with relatively large spheroidal or irregularly shaped 

 nuclei. 



The chief fibrous layer of this transitional portion is com- 

 posed of broad highly refractile fibres, capable of resisting the 

 action of acetic acid, and united into plexiform fasciculi. The 

 fasciculi separate from each .other at many points to permit 

 the passage of the horizontally coursing vascular trunks, which 

 are here very numerous. 



