198 



SPECIAL HISTOLOGY, 



monly contain some dark oil-drops, and more rarely one or 

 another, exhibits granules of yellow pigment. 



The straight and convoluted canals, together with the ge- 

 neral characters just described, present some differences. The 

 former, although originally of the considerable width of even 

 0'06 — O'l'", soon diminish, in consequence of the divisions 

 they undergo, to a diameter of 0-01 — 0014 — 0'018'", but in the 

 " bundles of Ferrein," again acquire the size of 0-02 — 0*24'". 

 With this diameter they enter the cortical substance, but subse- 

 quently, in the proper convoluted tubules, attain one of 0-033'", 

 though again somewhat constricted close to their commence- 

 ment. The membrana propria in the convoluted tubules is more 

 delicate (0-0003 — 0-0004'") and isolated with more difficulty, 

 the epithelium, on the contrary, is usually thicker, with cells 

 measuring 0*008— 0-012'" in width, and 0-004— 0-005'" in 

 thickness ; whilst in the straight tubules the cells are not more 



than 0-004 — 0*006'" wide, and 

 0'004"' thick. Physiologically, it 

 also seems to me worthy of remark, 

 that the last cells have clear, non- 

 granular contents, whence, also, the 

 medullary substance, in the blood- 

 less condition, appears whitish, 

 whilst the cortical exhibits a yel- 

 lowish hue. 



The Malpighian bodies present 

 a very peculiar structure. They 

 are to be regarded as appendages 

 of the convoluted tubuli uriniferi, 

 and contain imbedded in their epi- 

 thelium, and, as it may be said, 

 entirely filling their cavity, a 

 compact, rounded vascular plexus 

 — the glomerulus Malpighianus, the 



Fig. 247. 1, a Malpighian corpuscle, A, with the tubulus uriniferus springing 

 from it, B, C ; Human, x 300 diam.; figure half-diagrammatic: a, membrane of the 

 Malpighian body, continuous at b, with the membrana propria of the convoluted 

 tubule; c, epithelium of the Malpighian body; d, that of the tubule; e, detached 

 epithelium;/, v as offer ens ; g, vas efferens ; h, glomerulus Malpighianus. 2, three 

 epithelial cells from the convoluted tubule, x 350 diam.; one with oil-drops. 



