PASSAGE OF URINE INTO THE BLADDER. 449 



which its rate and mode of entrance has been watched in 

 cases of ectopia vesicee, i.e., of such fissures in the anterior 

 and lower part of the walls of the abdomen, and of the 

 front wall of the bladder, as expose to view its hinder wall 

 together with the orifices of the ureters. Some good 

 observations on such cases were made by Mr. Erichsen. 

 The urine does not enter the bladder at any regular rate, 

 nor is there a synchronism in its movement through the 

 two ureters. During fasting, two or three drops enter the 

 bladder every minute, each drop as it enters first raising 

 up the little papilla on which, in these cases, the ureter 

 opens, and then passing slowly through its orifice, which 

 at once again closes like a sphincter. In the recumbent 

 posture, the urine collects for a little time in the ureters, 

 then flows gently, and if the body be raised, runs from 

 them in a stream till they are empty. Its flow is increased 

 in deep inspiration, or straining, and in active exercise, 

 and in fifteen or twenty minutes after a meal. 



The same observations, also, showed how fast some 

 substances pass from the stomach through the circulation, 

 and through the vessels of the kidneys. Ferrocyanide of 

 potassium so passed on one occasion in a minute : vegetable 

 substances, such as rhubarb, occupied from sixteen to 

 thirty-five minutes ; neutral alkaline salts with vegetable 

 acids, which were generally decomposed in transitu, made 

 the urine alkaline in from twenty-eight to forty-seven 

 minutes. But the times of passage varied much , and the 

 transit was always slow when the substances were taken 

 during digestion. 



The urine collecting in the urinary bladder is prevented 

 from regurgitation into the ureters by the mode in which 

 these pass through the walls of the bladder, namely, by 

 their lying for between half and three quarters of an inch 

 between the muscular and mucous coats, and then turning 

 rather abruptly forwards, and opening through the latter, 

 it collects till the distension of the bladder is felt either 

 GG 



