XX.] 



LYMPHATIC GLANDS. 



23$ 



(fig. 222). These trabeculae are continued into the medulla, where 

 they branch, become finer, and anastomose to form an irregular net- 

 work. The lymphoid tissue lies in the meshes of this trabecular 

 framework, but everywhere separated from it by a lymph sinus or 

 lymph channel. 



In the cortex the alveoli are arranged in a regular manner, and 

 the greater part of each alveolus is occupied by a mass of adenoid 

 tissue crowded with leucocytes ; but this follicular substance is 

 everywhere separated from the capsule and trabeculse by a lymph 

 sinus, traversed by a network of fine fibrils with flattened cells 

 lying on them at the points of intersection. The network 

 is coarser than that of the adenoid tissue, and it contains a few 

 leucocytes. It, as well as the trabeculse, is covered by a layer of 

 sinuous endothelium. The medulla is also occupied by adenoid 

 tissue crowded with leucocytes, but the lymphoid tissue forms 



FIG. 222. L.S. Cervical lymph glands of Dog. c. Capsule ; 8. lymph sinus ; F. Follicle ; 

 a. Medullary cord ; b. Lymph paths of the medulla ; V, Section of a blood-vessel ; 

 11 F. Fibrous part at the hilum, x 10. 



branching or anastomosing cords medullary cords each one sur- 

 rounded by its lymph sinus. The medullary cords are continuous 

 with the follicular substance in the cortical alveoli. Near the centre 

 of the lymphoid tissue of the alveoli are clearer areas, the lymph- 

 knots or germ-centres. In them mitosis goes on rapidly, but it 

 requires a high power to discern the stages of the division of the 

 nuclei. The lymph sinuses are continuous throughout the gland, 

 and they are the channels through which the lymph moves. Some 

 glands are pigmented. 



LYMPHATIC GLANDS. 



1. Lymphatic Glands.- Harden in 5 per cent, ammonium 

 bichromate or alcohol the lymphatic glands of the mesentery of a 

 cat or calf, or those found in the neck or under the lower jaw of a 



