67 6~ Section of lymphatic gland tissue, a. Trabeculse. 6. 



THE SKIN AND ITS APPENDAGES. 1135 



appears to serve the purpose of maintaining the gland-pulp in the centre of the 

 space in its proper position. 



On account of the peculiar arrangement of the framework of the organ, the 

 gland-pulp m the cortical portion is disposed in the form of nodules and in the 

 medullary part in the form of 

 rounded cords. It consists of 

 ordinary lymphoid tissue, be- 

 ing made up of a delicate re- 

 ticulum of retiform tissue, 

 which is continuous with that 

 in the lymph-paths, but mark- 

 ed off from it by a closer retic- 

 ulation ; in its meshes are 

 closely packed lymph-corpus- 

 cles, traversed by a dense 

 plexus of capillary blood-ves- 

 sels. 



The afferent vessels, as 

 above stated, enter at all parts 

 of the periphery of the gland, 

 and after branching and form- 

 ing a dense plexus in the sub- 

 stance of the capsule, open 

 into the lymph-sinuses of the cortical part. In doing this they lose all their 

 coats except their endothelial lining, which is continuous with a layer of similar 

 cells lining the lymph-paths. In like manner the efferent vessel commences 

 from the lymph-sinuses of the medullary portion. The stream of lymph carried 

 to the gland by the afferent vessel thus passes through the plexus in the capsule 

 to the lymph-paths of the cortical portion, where it is exposed to the action of the 

 gland-pulp ; flowing through these, it enters the paths or sinuses of the medullary 

 portion, and finally emerges from the hilum by means of the efferent vessel. The 

 stream of lymph in its passage through the lymph-sinuses is much retarded by 

 the presence of the reticulum. Hence morphological elements, either normal or 

 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. 

 Many lymph-corpuscles pass with the efferent lymph-stream to join the general 

 blood-stream. 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 

 trabeculae, 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. 677) is the principal seat of the sense of touch, and may be 

 regarded as a covering for the protection of the deeper tissues ; it plays an 

 important part in the regulation of the body temperature, and is also an excretory 

 and absorbing organ. It consists principally of a layer of vascular tissue, named 

 the derma, corium, or cutis vera, and an external covering of epithelium, termed 

 the epidermis or cuticle. On the surface of the former layer are the sensitive 

 papilla; and within, or imbedded beneath it, are certain organs with special 

 functions, namely, the sweat-glands, hair-follicles, and sebaceous glands. 



