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THE ELECTRO-MOTIVE CHANGES ACCOMPANYING ACTIVITY 
IN THE MAMMALIAN URETER. 
By W. a. Jolly. (From the Physiology Laboratory, South African 
College.) 
The ureters of rabbits and monkeys were used in this research. They 
were either isolated and perfused with Ringer's solution at body tem- 
perature, or the electrodes were applied to the ureter in situ in the decapitate 
preparation or anaesthetised animal. 
Einthoven's string galvanometer was employed, and the deflections of the 
instrument recorded photographically with a magnification of 660 diam. on 
moving sensitised paper. The wicks of two non-polarisable electrodes are 
applied to the ureter. The right-hand electrode, which is connected with the 
lower end of the string of the galvanometer, and negativity of which relative 
to the left-hand electrode causes an ascent of the recorded curve, is applied 
proximally at a point close to the pelvis of the kidney. The left-hand 
electrode, whose negativity depresses the curve, is applied distally at a point 
nearer the bladder. 
When the electrodes are near to each other, e. g. 1 to 3 cm. apart, the 
form of curve recorded is shown in Figs. 1 to 4. The curve consists of (1) 
an initial downward deflection, indicating positivity of the right-hand or 
proximal electrode ; (2) a steep upward deflection giving a sharp summit ; 
the curve then falls steeply, and there is (3) a second downward deflection ; 
the curve then tends to run more or less horizontally for a time in the 
neighbourhood of the zero line, and is terminated by (4) a slow ascent and 
descent. 
It is evident that we have to do here with an electrical variation which 
resembles very closely the electro-cardiogram. So close is the correspondence 
between the two variations that one is led to conclude that they are 
essentially of the same nature, and I propose to make use, in describing the 
summits of the ureter variation, of the lettering Q, R, S, T, introduced by 
Einthoven for the electro-cardiogram. 
Figs. 1, 2, 3 and 4 are obtained from the isolated ureter of the rabbit, 
perfused with warm Ringer's solution. In the case of Figs. 1 and 2 the 
