606 



SPECIAL HISTOLOGY. 



All these vessels and nerves are supported by a connective tissue, 

 which, at the same time, serves as a stroma for the secreting elements, 

 and is much more developed in the medullary substance than in the 

 cortical. At the surface of the gland, it is condensed into a membrane, 

 often very distinct, O'Ol 0*02 of a line thick, which is but loosely con- 

 nected with the fibrous tunic, partly supports the superficial capillary 

 plexus, and is continuous with the internal stroma by numerous delicate 

 processes. 



In inflammations and exudations, the stroma is frequently so much 

 condensed as to be apparent on the most superficial inspection, or even, 

 more or less to compress the tubuli uriniferi. The additional elements 

 consist chiefly of a fibrinous exudation, presenting various stages of 

 transition into connective tissue, partly also of such forms as are pecu- 

 liar to immature normal connective tissue, as fusiform cells, &c. In the 

 case of the Malpighian bodies, these new formations present the form 

 of concentric, often very thick deposits, which constrict the afferent and 

 efferent vessels, thus inducing atrophy of the glomerulus, and very 

 essentially and prejudicially affecting the secretion of urine. In other 

 cases the increase of the stroma is only apparent, and depends upon the 

 atrophy of the secreting elements. 



FIG. 250. Transverse section through some straight cortical tubules, magnified 350 

 diameters; from Man: a, transverse section of tubuli urinifcri, the membrana propria only of 

 which remains ; b, similar tubules, with the epithelium still remaining; c, stroma of connec- 

 tive tissue, with elongated nuclei ; d, cavity in which a Malpighian corpuscle was con- 

 tained. 



FIG. 251. Epithelium of the pelvis of the Human kidney, magnified 350 diameters: A, 

 isolated cells; .B, the same in situ: a, small; 6, large tessellated cells; c, the same with 

 nucleated corpuscles in the interior; d, cylindrical and conical cells from the deeper layers; 

 c, transitional forms. 



