THE URINARY ORGANS. 213 



of the cortical substance and of the pyramids; when this portion 

 of the circulatory apparatus, especially in perpendicular sections, 

 may be very satisfactorily made out. For the same purpose, 

 kidneys injected from the veins are employed, in which not only 

 the capillary plexus, but the glomeruli are filled; and for the 

 study of the vasa efferentia, preparations not completely filled 

 from the arteries are suitable. The course of the tubuli 

 uriniferi should be studied in fine sections of kidneys hardened 

 by immersion in alcohol, by boiling in dilute nitric acid and 

 drying (Wittich), or by chromic acid, and rendered transparent 

 by acetic acid; or in sections, made with the double-bladed 

 knife, of recent, as well as of injected kidneys, in which the 

 most important conditions, even the divisions of the "ducts of 

 Bellini," may be observed. Nevertheless, it is always expedient 

 to inject the tubuli uriniferi ; and for this purpose, among the 

 Mammalia, the Horse appears to be best adapted. This filling 

 may happen, in consequence of accidental extravasation into the 

 Malpighian capsules ; in the injection of the arteries by this 

 means, however, rarely more than the convoluted tubuli are 

 filled ; or it may be effected by injection from the ureter with 

 the aid of the air-pump (Huschke, Isis, 1826), or the pelvis of 

 the kidney being kept filled, if an endeavour be made by the 

 kneading of it with the hand, to force the material into the 

 " ducts of Bellini," and beyond them (Cay la) . By means of a 

 very fine canula, the individual tubuli may also be injected 

 directly from the papilla.'] 



Literature. — M. Malpighi, f De Renibus, in Exercit. de 

 vise, struct. j J Al. Sehumlansky, ' Diss, de structura renum, 

 c. tab. Argentor. 1782, 4to ; W. Bowman, ' On the structure 

 and use of the Malpighian Bodies of the Kidney/ in *. Phil. 

 Trans./ 1842, I, p. 57; C. Ludwig, l Beitrage zur Lehre vom 

 Mechanismus der Harnsecretion/ Marburg, 1843 ; and Art. 

 1 Niere/ in Wagner's ' Handw. d. Physiolog./ II. p. 628 ; 

 J. Gerlach, in ' Muller's Archiv.', 1845 and 1848 ; Kolliker, 

 in ' Mull. Archiv./ 1845; Remak, in 'Froriep's N. Notiz./ 

 No. 786, 1845, p. 308 ; F. Bidder, in < Mull. Archiv./ 1845, 

 and ' Untersuch. iiber die Geschlechts- und Harnwerkzeuge 

 der Amphibien/ Dorpat, 1846 ; J. Hyrtl,. in ' Zeits. d. Wien. 

 Aerzte/ 1846 ; [Jos. Toynbee, ( On the Intimate Structure of 

 the Human Kidney/ ' Med. Chirur. Transact./ 2d Ser. vol. II, 



