408 



MANUAL OF HISTOLOGY. 



portion of the tissue in question merges into a formless connective-tissue 

 mass, not unfrequently very rich in fat-cells. 



Internally the capsule gives off a very extensive system of either simple 

 or extremely complicated septa (b, b, c), which divide the interior of the 

 organ into a number of intercommunicating cavities by splitting up and 

 again becoming united. These spaces are occupied by the proper lym- 

 phoid tissue. 



The septa correspond in structure with the tissue of the capsule. 

 They consist of fibrous connective-tissue, intermixed with smooth mus- 

 cular fibres. These latter are found in certain cases in large number, 

 as in the inguinal, axillary, and mesenteric glands of the ox (His). 

 According to Schwartz, the muscular fibres at the line of junction of the 

 medullary and cortical portions have a principally radiating arrangement. 

 The partitions of which we are speaking usually spring from the interior 

 of the capsule, with broad bases, between the rounded ends of the follicles, 

 descend perpendicularly between the latter, and undergo a change below, 

 where, as we shall soon see, the lymphoid tissue presents likewise a differ- 

 ent arrangement. At the transition from cortical to medullary substance 

 a general splitting up and subdivision of these connective-tissue plates 

 take place, the latter decreasing greatly in thickness. But no follicle is 

 completely ensheathed at its under surface in this system of septa. On 

 the contrary, either one or several gaps, or even wide deficiencies, are left, 

 through which the follicular tissue comes into immediate contact with 



the medullary substance. 



s> i i i PI n 



the 



In the same way 

 partitions passing in- 

 wards between adjacent 

 follicles may be inter- 

 rupted by massive bridges, 

 as it were, of lymphoid 

 tissue, by which these 

 are connected one with 

 another. 



223. 



By means of this ar- 

 rangement of partitions 

 just mentioned, the corti- 

 cal portion of each lymph- 

 node is divided into a 

 smaller or larger num- 

 ber of usually roundish 

 bodies (fig. 399, b, c) 

 known as the follicles. 

 These, however (figs. 398, 

 d, and 399), do not come 

 into contact with the sur- 

 face of the septum ; there 

 remains rather a remark- 

 able interspace, of greater or less breadth, between the two, called usually 

 the investing space of the follicle (fig. 399, i). 



The follicles themselves may be either closely crowded together or moro 

 or less widely separated, and are arranged sometimes in a single layer, and 



Fig. 399. Follicle from the lymphatic gland of a dog in vertical 

 section, a, reticular sustentacular substance of the more 

 external portion; 6, of the more internal, and c, of the most 

 external and finely webbed part on the surface of the follicle; 

 d, origin of a tliick lymph-tube ; e, the same of a thinner one ; 

 /, capsule; g, septa; AT, division of one of tbe latter; i, invest- 

 ing space of the follicle with its retinacula; A, vas afferens; 

 //, attachment of the lymph-tubes to the septa. 



