THE UBIXIFEEOUS TUBES. 



933 



Origin, course, and connections of the uriniferous tubules. When the 

 tubuli uriniferi are followed in their apparent course, the straight tubes are 



Fig. 653. PORTION OP THE URINIFEROUS TUBES, Fig. 6 3. 



MAGNIFIED (from Baly). 



A, portion of a convoluted tube from the cortical sub- 

 stance ; B, epithelial cells from the interior of the tube, 

 magnified 700 diameters. 



easily traceable from the Malpighian pyramids 

 into the pyramids of Ferrein, and from these 

 into the tubuli contorti. Thus, after the obser- 

 vations of Bowman bad demonstrated the con- 

 nection of the Malpighian corpuscles with the 

 tubuli contorti, it appeared natural to believe 

 that the tubuli contorti at one extremity com- 

 menced in capsules of Malpighian corpuscles, 

 and at the other were continued into straight 

 tubules, which opened at the summits of the 

 papillse. It appears, however, from the con- 

 current testimony of recent writers, that con- 

 siderable complexity of arrangement intervenes between the terminations of 

 the straight tubes and the commencements of the tubuli contorti, with 

 which the Malpighian corpuscles are connected. 



It may be considered as certain from the researches of Ludwig and 



Fig. 654. 



Fig. 654. TRANSVERSE SEC- 

 TION OF A RENAL PAPILLA 

 (from Kolliker). ^ 



a, larger tubes or papillary 

 ducts ; 6, smaller tubes of 

 Henle ; c, blood-vessels, dis- 

 tinguished by their flatter epi- 

 thelium ; d, nuclei of the 

 stroma. 



Zawarykin conducted by 

 means of injections, and 

 from those of Schweigger- 

 Seidel by means of isola- 

 tion of the tubules ia small 

 animals, that the tubuli 

 contorti which commence 

 ia the Malpighian cor- 

 puscles are continued into 

 the looped tubes of Henle, 



and that these open into the straight tubules or ducts of Bellini, either 

 directly or through the intervention of convoluted tubes of junction of 

 larger size, said by Schweigger-Seidel to be always present. According 

 to Henle, the straight tubules turn rather sharply round near the surface of 

 the kidney, and again course inwards ; and this appearance, which has been 

 corroborated by other observers, he believes to result from anastomoses of 

 the tubules in arches, two and two. It must be regarded as a question still 



