386 HEEMAN 0. MOSENTHAL 



Therefore we are justified in assuming that cerebral edema may be an acci- 

 dental accompaniment of the uremic state, but that it cannot be its cause. 

 The venous infusion of urine, or urinary constituents, such as urea, 

 will not result in any untoward symptoms unless the excretion of such 

 substances by the kidney is checked. If the infusion is preceded by 

 ligation of the ureters, vomiting, diarrhea, etc., develop much more 

 rapidly than if the latter operation had been the sole procedure and the 

 venous injection had no tbeen resorted to. This demonstrates that the 

 urinary waste products have a distinct bearing upon the problem of uremia. 

 Voit has furnished proof for this contention by a very striking experiment. 

 A small dog, weighing 3 kg., was given 18 gm. of urea; the animal was 

 allowed to drink as much water as it chose, and within 24 hours the urea 

 was eliminated without difficulty ; the effective excretion was accomplished 

 largely by polyuria. If the experiment, was conducted as before, except 

 that the water intake was restricted, an entirely different picture developed : 

 a few hours after the administration of the urea, there was evident pros- 

 tration, and shortly afterwards violent -attacks of vomiting came on, which 

 were repeated on this as well as the following day ; in the meantime, the 

 dog became progressively weaker and more apathetic, there were marked 

 muscular twitchings and cramps, and the animal was evidently in a very 

 precarious state. All these symptoms were, however, set aside when water 

 was again administered and polyuria established. From these observations 

 it is possible to conclude that large amounts of urea may readily pass 

 through the body without detrimental effect, although the accumulation of 

 urea in the blood and tissues, because of insufficient kidney action, is 

 fraught with dire consequences. On the other hand, not all investigators 

 obtained similar results. Thus, after injection experiments, Astaschewsky 

 denied that either urea or creatinin had any toxic effect ; he believed the 

 mineral salts, especially potassium, to be of much more importance. Since 

 the cause of uremia can not be recognized in any single substance it be- 

 comes evident that from the practical point of view it will be preferable not 

 to consider uremia to be brought about by this or that substance, but by 

 a retention of all the solid constituents ordinarily contained in the urine. 

 The particular cause of the renal insufficiency is of little moment in this 

 connection. A variety of conditions, very unlike each other from the 

 clinical, anatomical or pathologicophysiological point of view, may be 

 responsible for the oliguria or anuria. Thus the inspissation of the blood 

 entailed by cholera or any marked diarrheic state, eclamptic seizures, acute 

 or chronic nephritis, mechanical obstruction of both ureters or the urethra 

 may diminish the urinary output. The same effect is produced (Bartels 

 (d) ) in some cases of edematous nephritis when there is a rapid elimina- 

 tion of fluid. Presumably under these circumstances the solids are not 

 eliminated with equal speed, and an inspissation of the blood, the possible 

 cause of uremic symptoms, results. 



