THE VASCULAK GLANDS. 



391 



gland tissue proper consists of an outside firmer cortical portion, and an 

 inside soft dark medullary portion. 



(1.) The cortical portion is divided into (Fig. 269) an external nar- 

 row layer of small rounded or oval spaces, the zona glomerulosa, made 

 by the fibrous trabeculae, containing multinucleated masses of proto- 

 plasm, the differentiation of which into distinct cells, cannot be made 

 out. (b) A layer of cells arranged radially, the zona fasciculata (c). 

 The substance of this layer is broken up into cylinders, each of which 

 is surrounded by the connective-tissue framework. The cylinders thus 

 produced are of three kinds one containing an opaque, resistant, highly 

 refracting mass (probably of a fatty nature); frequently a large number 

 of nuclei are present; the individual cells can only be made out with 

 difficulty. The second variety of cylinders is of a brownish color, and 

 contains finely granular cells, in which are fat globules. The third 

 variety consists of gray cylinders, containing a number of cells whose 

 nuclei are filled with a large number of fat granules. The third layer 

 of the cortical portion is the zona reticularis (not shown in Fig. 269). 

 This layer is apparently formed by the breaking up of the cylinders, the 

 elements being dispersed and isolated. The cells are finely granular, 

 and have no deposit of fat in their interior: but in some specimens fat 

 may be present, as well as certain large yellow granules, which may be 

 called pigment granules. 



(2.) The medullary substance consists of a coarse rounded or ir- 



Fio. 270. Section through a portion of the medullary part of the supra-renal of guinea-pig. 

 The vessels are very numerous, and the fibrous stroma more distinct than in the cortex, and is 

 moreover reticulated. The cells are irregular and larger, clean, and free from oil globules. X 

 Co. K. Alcock.) 



regular mesh work of fibrous tissue, in the alveoli of which are masses of 

 multinucleated protoplasm (Fig. 270); numerous blood-vessels; and an 

 abundance of nervous elements. The cells are very irregular in shape 



