106 THE KIDNEYS, BY C. LUDWIG. 



bloodvessels which pass from one to the other form the loose 

 connection between the capsule and the parenchyma of the 

 kidney. No fibrillated connective tissue exists between the 

 tortuous portions of the urinary tubules. An exception, how- 

 ever, very frequently exists, besides the above-mentioned in- 

 vesting layers, in the case of the tissue immediately surrounding 

 the Malpighian corpuscles, and especially those which lie close 

 to the medulla. These are often enclosed by fibrous connective 

 tissue. Elsewhere only isolated small fusiform cells lie be- 

 tween the blood capillaries and urinary tubules of the labyrinth, 

 which are so placed that the long axes of their nuclei stand at 

 right angles to those of the urinary tubuli. These cells do not, 

 however, in any way bind the convolutions of the urinary 

 tubuli either to one another or to the bloodvessels, as can be 

 demonstrated from the examination of kidneys affected with 

 acute oedema and obstructed flow of urine. In such kidneys 

 the cortex is considerably larger than that of the opposite 

 sound organ, and the convolutions of the tubes must conse- 

 quently be put considerably upon the stretch; and we may see 

 on section a remarkable separation of the capillaries and 

 urinary tubules. The spaces between the tubes of the medulla 

 in the immediate neighbourhood of the papilla are filled with 

 a distinctly fibrillated connective tissue surrounding the uri- 

 nary tubuli in a concentric manner; the nearer we approxi- 

 mate the limiting layer, the more delicate becomes the 

 fibrillation and the more abundant the cellular elements which 

 give off from their fusiform or stellate bodies fine processes 

 often of considerable length. 



NERVES. The nerves penetrate the kidneys with the vessels, 

 and present ganglia in their course. Anatomical investigation 

 has furnished us with no information in regard to their mode 

 of termination. The results of experiment show that besides 

 motor fibres effecting the contraction of the circular muscular 

 coat of the smaller arteries, they also contain sensory fibres. 



Historical points in reference to the anatomy of the uri- 

 nary tubules in Mammalia. The straight tubuli of the medulla 

 have been known since the time of Bellini in the seventeenth 

 century, the tortuous since the time of Ferrein in the middle 



