“A preliminary study of the toxicological action of thorium”

Our experiments comprised the third series in a study, still in progress, of the toxicology of rare elements. 1 They were twenty-seven in number, and were performed on as many animals (frogs, mice, dogs). They were carried out before Baskerville's announcement of his discovery that thorium contains two new elements, named by him berzelium and carolinium. Publication of our results was deferred because of our desire and intention to complete the work with a study of the toxicological effects of these two new elements, which Professor Baskerville has generously agreed to furnish at a later stage in his investigations. The foregoing communication by Professor Sollmann has induced us, however, to present our results as they stand.

In some of the early experiments (1900) it was found that thorium (nitrate) had a uniform precipitative effect on various connective tissue mucoids. In a study with Professor Loeb (1902), on the antitoxic influence of ions, thorium (nitrate) was used as a tetravalent element, and was found to exert only very slight, almost inappreciable antitoxic effects in mNaCl, with fertilized Fundulus eggs as the indicators. At that time we observed a strong precipitative effect of thorium on protoplasm, and a marked toxicity on various fishes, and on both fertilized and unfertilized Fundulus eggs in sea water, although these facts were not recorded in our paper.

In the experiments on frogs and warm-blooded animals the tetrachlorid was used exclusively. Of our results the following were in harmony with those reported by Brown and Sollmann : Thorium exerts marked astringent action. The chlorid is acid in reaction (in water). The aqueous solution of the chlorid blanched and hardened tissues, proteins were precipitated by it, and blood not only precipitated but blackened. Injected directly into the circulation even very small doses caused intravenous precipitation, and resulted fatally. Subcutaneous injection resulted in local necrosis. We have had no experiments with thorium in citrate solution nor on the excretion of thorium.