THE URINARY TRACT. 745 



the conclusion that the secretion or elimination of this coloring matter takes 

 place only in those portions of the tubuli uriniferi which are covered by the 

 epithelia having the rods (epithelium a batonnets). Whether the secretion 

 of the specific principles of the urine takes place in precisely the same fashion 

 as the elimination of coloring matters, he regards as impossible of demonstra- 

 tion experimentally. In a recent monograph, Charcot * regards the tubuli 

 contorti and the loops of Henle, particularly the ascending branches of the 

 loops, as the real glandular part of the kidney. Heidenhain, however, did 

 not associate the rods with the process of secretion, for he observed a similar 

 structure also in the smaller ducts of the parotid and submaxillary glands, 

 the same formation in the latter structure being already known to Henle 

 and Pfliiger. In the acini of the glandula submaxillaris and in the other 

 acinous glands he could not discern them. E. Klein t asserts having ob- 

 served that the rods or fibrils of Heidenhain, when looked at from the sur- 

 face, are connected into a net-work, so that they are more probably septa 

 of a honeycombed net-work seen in profile. What the intimate nature 

 of these formations is, neither of the above-named authors attempts to 

 explain. 



Since the reticular structure of all protoplasmic formations, including 

 therefore epithelium, was demonstrated by C. Heitzmann, the question has 

 been, what the reticulum present in the protoplasm is. A proof of the reticu- 

 lum being the living matter proper rests upon the fact that, both in normal 

 and in morbid processes, the new formation of corpuscular elements starts 

 from the points of intersection in the reticulum. This so-called endogenous 

 new formation of living matter is especially plain in the inflammatory process 

 invading epithelial formations. Here, it is important to note, the reticulum 

 at first becomes coarse ; next, it coalesces into lumps, which, being at first 

 homogeneous, in turn assume a reticular structure themselves, and now rep- 

 resent so-called inflammatory or pus-corpuscles. These corpuscles at first 

 remain in connection with the neighboring reticulum by means of delicate 

 filaments, which are portion and part of the reticulum. Later, when the in- 

 flammatory corpuscles which have originated in the interior of an epithelium 

 become extruded from its interior, the newly formed corpuscles represent 

 pus-corpuscles. 



In conducting my researches, I have studied the kidneys of the rabbit, 

 pig, dog, and man, all of them being preserved and hardened in a solution of 

 chromic acid. I have, therefore, no observations to report upon the form- 

 changes of the epithelia, but have studied the changes in the interior structure 

 of the epithelia in the inflamed human kidney. These investigations enable 

 me to maintain that the reticular structure of the epithelium of the kidney is> 

 really a formation of living matter. 



Upon closely examining the epithelia of the tubuli uriniferi in the kidneys 

 of the above-named animals, we readily perceive, with comparatively low 

 powers of the microscope (400 or 500 is sufficient), the presence of rod-like 

 formations in the epithelia of the tubuli contorti, in the irregular tubules, in 

 the ascending branch of the looped tubules, and in the intercalated tubules, 

 entirely in accordance with Heidenhain's assertions. The drawings of the 

 rodlets, as given by Heidenhain arid copied by Klein and other writers, give 

 an exaggerated idea of the real appearance of the rods. Even under a high 



" LCQOIIS sur les Conditions Patliogeniques <le 1'Albumiimrie," Paris, 1881. 

 t "Atlas of Histology," London, 1880. 



