414 



MANUAL OF HISTOLOGY. 



tions in the cortical portion, the septa do not come into contact with the 

 lymphoid .substance here either. On the contrary, we find, as in the 

 first case, so here also, the lymph-tubes and septa, or, where the latter 

 are absent, the lymph-tubes alone, separated from one another by a nar- 

 rower or broader interval analogous to the investing space of the follicle. 



There now remains for consideration the contents of these reticulated 

 passages of the medullary substance. Here, as in the investing space of 

 " the follicles, a certain number of lymph-corpuscles are to be found, which 

 may be removed with a brush. Besides these, we observe that a con- 

 nective-tissue network, with a varying amount of nodal points, nuclei, and 

 processes, occupies the passages with wide straggling meshes (fig. 406, b; 

 405, I). Springing on the one hand, from the septa of the gland, its fibres 

 sink on the other into the reticular tissue of the lymph-tube, or, where 

 there are no septa, connect one lymph-tube with another. 



Not unfrequently in the mesenteric glands, as for instance in the 

 pancreas Asellii of the rabbit, some very interesting points in regard to 

 the cellular network occupying the interstices of the medullary substance 



may be observed (fig. 407, 

 c). The bodies of the cells 

 appear tense and swollen : 

 they have, moreover, no 

 membrane. Their processes 

 or ramifications are like- 

 wise thickened and broad. 

 Within both the bodies 

 and their processes, be- 

 sides soft -looking nuclei, 

 isolated lymph corpuscles 

 are to be seen ( W. Muller, 

 Frey\ which may have 

 come there either by im- 

 migration or possibly by 

 generation on the spot. 

 The possibility of this 

 latter alternative remains, 

 however, still a matter of 

 uncertainty. 



If we follow up the rebi- 

 cular interstices of the 

 medullary substance to the 

 boundary of the latter, we 

 have no difficulty in re- 

 cognising the fact (especi- 

 ally if we carry our eye 

 along one of the partitions) 

 that they lead into the investing spaces of the follicles (fig. 405). 



From all this we learn that the lymph-nodes are formed of a system of 

 cavities (imperfectly bounded by septa) which are occupied by lymphoid 

 matter in the cortical portion by the follicles, and in the medullary by 

 the lymph-tubes but always so arranged that the lymphoid substance 

 does not come into contact with the fibrous septal system. Thus we 

 have both a series of spaces, encasing, as it were, the follicles, (investing 

 spaces), and a system of intercommunicating passages enveloping the 



Fig. 407. 



