66 E. J. STIEGLITZ 



Realizing that this conspicuous antidiuresis or inhibition to 

 water ehmination might be due to some vasodilator, depressor 

 effect of the ferric ammonium citrate interfering with the normal 

 circulation to the kidney, we performed two experiments (K84 

 and K85) to ascertain this point. Dogs were used; the animals 

 put under light ether anesthesia and cannular connections made 

 from the carotid artery to a manometer set to record on a kymo- 

 graph. The tracings obtained showed a prompt, very brief drop 

 in the blood pressure of about 20 to 40 mm. when large doses 

 were injected very quickly into the femoral vein. Both experi- 

 ments gave the same results. This fall in pressure lasted only 

 for a few seconds, never as long as a minute, and following that, 

 the pressure remained at normal. Therefore it is impossible to 

 ascribe the decrease in urine flow following iron injections to any 

 depressor actions of the salt. 



Another possibility which suggested itself in this connection 

 was some change in the blood plasma, binding the 'free' water 

 and manifesting itself by disturbance of the thermoregulatory 

 processes and the production of fever, as recorded and discussed 

 by Balcar, Sansum and Woodyatt (75). Therefore throughout 

 the two above-described blood-pressure experiments the rectal 

 temperature was taken at frequent intervals. However, no 

 change in the slight and gradual fall of temperature, which 

 invariably accompanies ether anesthesia, was discovered; the 

 temperature curve fell uniformly, irrespective of the iron injec- 

 tions. Thus it is evident that the inhibition to the passage of 

 water due to the iron salt is neither the result of a depressor 

 action of the drug nor of changes in the blood plasma binding 

 the 'free' water. Moreover, the presence of iron, tending to 

 dehydrate rather than to hydrate the colloids, should increase 

 rather than decrease the 'free' water. 



However, Fischer (18, p. 295), in discussing saline diuresis, 

 makes the following statement: "the saline diuretics are nothing 

 but those salts which without being markedly poisonous are the 

 most powerful dehydrants of the body colloids. They owe their 

 action primarily not to any effect upon the kidney, but to an 

 effect upon the body as a whole. By diffusing into the tissues 



