184 V. E. HENDERSON. 



The experiments were carried out before Lindemann's paper came 

 into my hands, otherwise hints contained in it might, I believe, have led 

 to a greater success. The following variations upon the method employed 

 by other observers were made use of. In dogs under morphia and A.C.E. 

 the kidney and ureter were exposed, and freed from the surrounding 

 tissues ; especial care was taken to carefully clean the artery, vein, and 

 ureter, at the hilus of the kidney, so that all lymphatic connections were 

 broken. CannulaB were inserted in the ureters and the carotid artery 

 and the jugular vein. An injection of a concentrated solution of dextrose 

 (approx. 35 g. dextrose in 50 c.c. water) intravenously was given so as to, 

 firstly, make the animal as poor in water as possible, and, secondly, lower 

 as much as possible the percentage of electrolytes in the urine. During 

 the diuresis *records of the possible ureter-pressures were taken and 

 during its subsidence the ureter cannula was connected by a tube with 

 a small reservoir ; connecting tube and reservoir were filled with a 

 solution of indigo-carmine. The following protocol is given in full. 



EXP. XVII. Dog 8 kg. Operation as above. 



Blood- Ureter- Outflow. Drops 



Time pressure pressure per min. 



10.20 140 Ureter connections 



50 c.c. 50 / dextrose 144 90 20 opened after each 



10.50 140 84 6 observation 



10. 55 Ureter-pressure allowed to rise, and then ureter cannula connected with pressure- 

 vessel. 



Pressure 125 cm. H 2 O = approximately 92 mm. Hg (2 mm. only above the 

 pressure observed above). 



11.35 Slight blue tinge in urine of other kidney; fluid-level in reservoir had fallen 

 approximately 6 mm. = 8 c.c. H 2 0. 



12 Urine distinctly blue ; fall of fluid-level 10 mm. = approximately 13 c.c. H 2 0. 

 Blood-pressure 138 mm. 



Bight ureter ligatured, vessels ditto. Kidney removed. Washed. Tissue beneath the 

 capsule showed areas, especially towards the ends of the kidney, of mottled bluing. Kidney 

 bisected longitudinally; washed lightly with running water. Narrow wedge-shaped 

 stripes are to be seen, especially towards the ends of the kidney, which radiate from pelvis 

 to cortex, in which they are not to be made out or in which they are less distinctly 

 marked and wider but reach to the capsule. Parallel sections on either side show similar 

 pictures. Thin slices hardened in abs. ale. imbedded in paraffin and stained with alcohol 

 eosin. 



Histological examination of these blued areas showed abundant precipitates (crystalline 

 or granular) of indigo-carmine in the collecting tubules, and in the distal convoluted 

 tubules of the cortex, in many cases directly underlying the capsule, and in the tubules of 

 the ascending limb of Henle's loop. Deposits were also found but were not common in 

 the descending loop of Henle. In many of the convoluted tubules and in those of Henle's 



