112 



Chapter VII 



The oxygen used was the same in each of the three cases ; there- 

 fore any difference in the quantity of urine was not due to a different 

 degree of activity in the kidney. Yet in the second case there was 

 almost no diuresis whilst in the first and third there was copious 

 diuresis. 



(2) In control experiments starch in place of gelatine was added 

 to the Ringer's solution. The addition of soluble starch produces no 



SALINE 



GELATINE SALINE 

 SALINE 



SALINE STARCH 

 SALINE 



SALINE 



STARCH 

 SALINE 



FIG. 66. Urine = black area. Blood pressure = broken line. The black line just below 

 the blood pressure shows the oxygen consumption by the kidney. Abscissae = time in 

 hours. 



increase in the osmotic pressure of Ringer's solution but the fluid 

 has twice the viscosity of blood : yet when injections of Ringer's 

 solution with and without starch were made alternately the diuresis 

 was almost the same in every case. 



(3) A 5 per cent, solution of gum acacia has almost no greater 

 viscosity than has the saline solution, but on the other hand it has a 

 considerable osmotic pressure though not quite equal to that of the 

 plasma of the gelatine. The result was the same as that of injection 



