THE DUCTLESS GLANDS. 327 



renal capsules, or variously branched, and with the cavities of 

 the several branches communicating in and by common canals, 

 as in the thy m us (Fig. 107). These vesicles, like the acini of 

 secreting glands, are formed of a delicate homogeneous mem- 

 brane, are surrounded with and often traversed by a vascular 

 plexus, and are filled with finely molecular albuminous fluid, 

 suspended in which are either granules of fat, or cytoblasts, or 

 nuclei, or nucleated cells, or a mixture of all these. 



Structure of the Spleen. The spleen is covered externally 

 almost completely by a serous coat derived from the peri- 

 toneum, while within this is the proper fibrous coat or capsule 

 of the organ. The latter, composed of connective tissue, with 



FIG. 107. 



Transverse section of a lobule of an injected infantile thyinus gland (after K61- 

 liker) (magnified 30 diameters), a, capsule of connective tissue surrounding the 

 lobule ; ft, membrane of the glandular vesicles ; c, cavity of the lobule, from which 

 the larger bloodvessels are seen to extend towards and ramify in the spheroidal 

 masses of the lobule. 



a large preponderance of elastic fibres, forms the immediate 

 investment of the spleen. Prolonged from its inner surface are 

 fibrous processes or trabeculce, which enter the interior of the 

 organ, and, dividing and anastomosing in all parts, form a 

 kind of supporting framework or stroma, in the interstices of 

 which the proper substance of the spleen, or the spleen-pulp, is 

 contained. At the hilus of the spleen, or the part at which 



