On the metabolic influence of magnesium sulfate in dogs,with special reference to the partition of the nitrogenous constituents of the urine

In these experiments, in which relatively large doses of magnesium sulfate were given to dogs, abscesses and sloughing followed subcutaneous injections, but were not caused by intramuscular or intravenous injections nor by administrations per os. Very large doses of magnesium sulfate could repeatedly be injected intravenously without causing death, when care was taken to conduct the process slowly.

Daily fluctuations in the weight of the animals, as well as in the volume and specific gravity of their urines, resulted chiefly from diuretic or diarrheal influences and the consequent compensatory tendencies.

Administration per os caused diarrhea. Bone ash in the food appeared to exert only a mechanical diminution of such diarrheal tendencies. Injections under the skin or into a muscle or into the circulation failed to elicit any evidence of diarrhea, except in one doubtful case after subcutaneous application. On the contrary, such injections appeared to make the feces drier and harder than ordinarily, and the urine volumes greater.

If there was any effect on the quantitative elimination of solid matter in the feces, it was not more than a slight increase. The same may be said of the content of nitrogen in the feces, and also of the fecal discharge of magnesium (after intravenous injection of magnesium sulfate).

In a general way elimination of nitrogen in the urine was increased after the normal periods, but the increase was not sufficient to warrant the conclusion that it was a direct effect of the dosage. The observed absolute increase of urinary nitrogen was registered chiefly in the form of urea, although the relative excretion of the latter was below normal in one of the two main experiments.

The most striking and consistent effect on the partition of the urinary nitrogen was the continued absolute as well as relative increase of ammonia elimination throughout the whole of the dosage part of each metabolism experiment, in spite of the fact that the Folin method does not permit of complete recovery of ammonia from crystallized ammonio-magnesium phosphate.