612 SPECIAL HISTOLOGY. 



missed in fine, hardened sections, and especially in injected prepara- 

 tions. The glomeruli themselves may frequently be recognized when 

 naturally injected, and still better when artificially filled, which we may 

 very readily succeed in doing Avith any fine material thrown in by the 

 arteries. Similar injections, also, when successful, fill the whole capil- 

 lary plexus of the cortical substance and of the pyramids ; when this 

 portion of the circulatory apparatus, especially in perpendicular sec- 

 tions, may bo 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 

 va^a efferetitia, 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 ren- 

 dered 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 conse- 

 quence 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 endeavor be made by the 

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

 Bellini," and beyond them (Cayla). By means of a very fine canula, 

 the individual tubuli may also be injected directly from the papillce. 



Literature. — M. Malpighi, "De Renibus, in Exercit. de vise, struct. ;" 

 Al. Schumlansky, "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, "Beit- 

 rage zur Lehre vom Mechanismus der Harnsecretion," Marburg, 1843 ; 

 and Art. " Niere," in Wagner's " Handw. d. Physiolog.," II. p. 628; 

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

 Archiv.," 1845; Remak, in "Froriep's N. Notiz.," No. 786, 1845, p. 

 308; F. Bidder, in " Mlill. Archiv.," 1845, and " Untersuch. uber die 

 Geschlechts- und Harnwerkzeuge der Amphibien," Dorpat, 1846; J. 

 Hyrtl, in " Zeits. d. Wien. Aerzte," 1846 ; [Jos. Toynbee, " On the In- 

 timate Structure of the Human Kidney," "Med. Chirur. Transact.," 2d 

 Ser. vol. II., p. 303, 1846;] C. v. Patruban, " Beitriige zur Anatomic 



* [I have found that the Malpigliian corpuscles are filleil with much more difficulty, and 

 always imperfectly by injections thrown in by the veins. — DaC] 



