THK THYMTS GLAM'. 



b. Minute structure (Fig. 211). 



[The gland is surrounded by a connective capsule, which is 

 indented on the inner surface to form 

 a hilus through which blood-vessels- 

 course into the organ. 



The capsule sends in numerous fine 

 trabeculae. which form a connective- 

 tissue skeleton such as is found in all 

 lymphatic glands. The corpuscles of 

 the trabeculae possess elongated nuclei 

 from 0*019 t 0*028 mm. in length, 

 and o-oio to 0-015 mm - m breadth 

 (Tolldt). The trabeculae support a 

 network of blood-vessels. 



The meshes of this sustentaeular 

 tissue are filled with cells ; these are : 



(a) Lymphoid cells, rounded or oval, possessing a round nucleus 

 and nucleolus, and an extremely small amount of adhering proto- 

 plasm; the size of the nucleus is from o-oii to 0-015 mm. 

 (Tolldt). 



Fig. 211. 



St 



Dissection to show relations of the 

 thymus gland. 



/' . M. deltoideus. 



D.m. M. depressor mandibulae. 



L.J. M. latissimus dorsi. 



St M. sternocleidomastoideus. 



Tf Tympanic membrane. 



Th Thymns gland. 



From various sections from the thymus gland of Rana etculenta. G. H. 

 I. Complete gland (Hartnack, Oc. I, Syst 3). 



a Pigment-cella. 

 1 1. Portion of a section (Hartnack, Oc. I, Syst. 7) showing small corpuscles of Hassall. 



I 1 1. Portion of a section showing lubules with degenerating cells. 



a Capsule of lobe. 



6 Lobules. 



c Large corpuscle of TTaRall surrounded by normal tissue. 



IV. Nerve-cell? (corpuscle of Hassan), after Fleischl 



(3) Corpuscles of Hassall (Fig. 211 II, III, and IV) are. 

 rule, large bodies, but are subject to much variation in size. Their 



Y 



