THE SKIN AND ITS APPENDAGES. 



89 



morbid, are easily arrested and deposited in the sinuses. This is a matter of con- 

 siderable importance in connection with the subject of poisoned wounds and the 

 absorption of the poison by the lymphatic system, since by this means septic 

 organisms carried along the lymphatic vessels may be arrested in the lymph-sinuses 

 of the gland tissue, and thus be prevented from entering the general circulation. 

 The arteries of the gland enter at the hilum, and either pass at once to the gland- 

 pulp, to break up into a capillary plexus, or else run along the trabeculge, partly 

 to supply them and partly running across the lymph-paths to assist in forming the 

 capillary plexus of the gland-pulp. This plexus traverses the lymphoid tissue, 

 but does not pass into the lymph-sinuses. From it the veins commence, and 

 emerge from the organ at the same place as that at which the artery enters. 



THE SKIN AND ITS APPENDAGES. 



The skin (Fig. 67) is the principal seat of the sense of touch, and may be 

 regarded as a covering for the protection of the deeper tissues ; it is also an im- 

 portant excretory and absorbing organ. It consists principally of a layer of vascular 

 connective tissue, named the derma, corium, or cutis vercij and an external covering 

 of epithelium, termed the epidermis or cuticle. On the surface of the former layer 



Superficial 

 layers 

 Rete 



Xucosum 



Epidermif 



or 

 Cuticle 



Derma 



FIG. 67. A sectional view of the skin (magnified). 



are the sensitive papilla? ; and within, or imbedded beneath it, are certain organs 

 with special functions namely, the sweat-glands, hair-follicles^^ sebaceous glands. 

 The epidermis or cuticle (scarf-skin. Fig. 68) is an epithelial structure belong- 

 ing to the class of stratified epithelium. It is accurately moulded on the papillary 

 layer of the derma. It forms a defensive covering to the surface of the true skin, 

 and limits the evaporation of watery vapor from its free surface. It varies in 

 thickness in different parts. In some situations, as in the palms of the hands and 

 soles of the feet, it is thick, hard, and horny in texture. This may be partly due 



