“A preliminary communication on the pharmacology Of thorium”

Thorium nitrate precipitates proteins and is intensely astringent. Its intravenous injection is promptly fatal by embolism. Applied subcutaneously, it causes local necrosis. Administered by the stomach, even large doses have no appreciable effect.

Solutions in sodium citrate were found to be nonprecipitant and nonastringent. As much as 1 gm. of thorium nitrate, per kilogram of dog, injected subcutaneously and intravenously in citrate solution, had little acute action; however, the animals appeared depressed and became emaciated. The postmortem examination, made after several weeks, showed extensive and widespread calcification of tissues. Thorium could not be demonstrated in the calcified areas.

A method for the quantitative estimation of thorium was elaborated; this gave satisfactory results with urine, to which known quantities where added. But in actual experiments on animals it was found inaccurate, a large proportion of the injected thorium escaping detection. However, it was found that on intravenous or subcutaneous injection, the thorium appeared in the urine, and not in the feces. When administered by mouth, it appeared in the feces, but not in the urine. The conclusion appears justified that absorbed thorium is excreted by the kidneys, but that the metal is neither absorbed nor excreted through the intestine.