176 



V. E. HENDERSON. 



graph. The changes in volume of its contents were recorded with a 

 Hiirthle piston-recorder. The flow of urine from the other kidney was 

 usually simultaneously recorded by allowing the drops from a cannula 

 inserted in its ureter to fall upon one of a pair of tambours. Rabbits 

 were anaesthetized with urethane and A. c. E., dogs with morphia and 

 A. c. E. 



The factors which at once were seen to play a more or less essential 

 part will be considered in order, but first a word or two about the con- 

 tractions of the ureter musculature and the pressures produced by them. 

 Correctly these alone should be spoken of as the ureter-pressures. These 

 contractions seem normally to occur at very varying rates and often not 

 with a quite regular rhythm. They sometimes occur in roughly 

 rhythmical groups. They seem to increase in rate with the rate of 

 urine flow, e.g. 



EXP. XIII. 



EXP. XV. 



Dog. Bate of contractions 4 

 Later 6 ; 



Again 

 Dog. 

 Later 

 Again 



10: 

 13: 

 19: 



of urine f drops, per minute. 

 1 

 4 

 6 

 8 

 13-18 



Similar observations were made in rabbits. The increase in rate of 

 flow was produced by saline injections or caffeine. They often become 

 slightly more frequent as the pressure rises. They disappear in the dog 

 with a pressure of from 26 32 mm. Hg, in the rabbit at from 8 16 

 mm. Hg. A slight artificial rise in pressure often serves to excite them 

 or increase their rate when present. Stimulation of the splanchnic as 

 shown by Protopopow or of the hypogastric, as shown by Fagge 

 also, will often produce contractions in a ureter seemingly paralysed by 

 pressure. Adrenalin has the same effect. The slow return to a maximum 

 of the ureter-pressure after splanchnic stimulation in Figs. 3 and 4 is 

 due to their presence. When vigorous they may cause considerable 

 variations in pressure, e.g. in exp. XIV. Dog, with a ureter-pressure of 

 6 mm. Hg, several contractions occurred, each of which produced a rise 

 of 36 mm. Hg, rate 4 5 per minute. In a rabbit the greatest change 

 noticed was 12 mm. Hg. Irregularities due to these contractions were 

 in some cases avoided by allowing paralysis of the musculature due to 

 over-distension to supervene before beginning a series of observations. 



The phenomenon usually described as ureter-pressure has nothing 

 to do with the ureter but depends entirely upon the kidney. The first 

 factor in its production is what may best, perhaps, be termed the onco- 



