CHAP. XXVI.] STRUCTURE OF LYMPHATIC GLANDS. 275 



in the deeper parts of the gland. The epithelium, however, becomes 

 thicker and more opaque, so as often no longer to transmit the light 

 under the microscope, and by the action of acetic acid very nume- 

 rous nuclei are disclosed in it. He describes the elongated nuclei 

 in the substance of the (proper) membrane on which this modified 

 glandular epithelium rests, and appears to consider that the epi- 

 thelium is in constant decay and renovation, being shed as a 

 secretion into the cavity of the ducts, to mingle with and modify 

 the passing lymph. * 



From the examinations we have made of the recent glands of 

 the lower mammalia, we are disposed to agree in most particulars 

 with this description. The very delicate simple layer of transpa- 

 rent nucleated cells lining the lymphatic vessel ere it enters the 

 gland, becomes in the gland a very thick and rather opaque granu- 

 lar mass loaded with nuclei, in the debris of which are apparent a 

 great abundance of nucleated cells of different sizes, many of them 

 precisely resembling the white or colourless lymph corpuscles pre- 

 sently to be described. We lean strongly to the opinion that these 

 corpuscles are set free to a large amount, though, perhaps, not ex- 

 clusively, from the surface of the intra-glandular passages. The 

 structure of the lymphatic glands offers many difficulties to the ana- 

 tomist, and there can be little doubt that further research would 

 discover peculiarities as yet undetected. 



The lymphatic glands are well supplied with blood. The arteries 

 and veins derived from neighbouring sources subdivide together on 

 the surface, and penetrate between the ducts, carrying in with them 

 for some distance a sheath derived from the capsule. The capil- 

 lary network is probably spread out on the exterior of the ducts, 

 i. e. in the interstices of the plexus which these form in the gland ; 

 but it cannot be said that the exact relation of the blood-vessels to 

 the abundant granular matter of the ducts has been as yet unequi- 

 vocally demonstrated. The capillaries are very fine, their meshes 

 large, and they anastomose throughout. 



In injections of the ducts of the glands, the mercury is observed to 

 find its way very readily into the veins, but not into the arteries ; 

 and it has been concluded by Fohmann, that this indicates a natu- 

 ral communication between these sets of vessels in the glands. This 

 view is certainly rendered plausible by the proved termination of 

 the lymphatics in the veins of the neck, and by the fact which 

 appears to be established by the observations of Fohmann, Lauth, 



* Anatomical and Pathological Observations. 



