“Comparative physiological action of salts of neodymium,præseodymium and lanthanum”

The experiments were undertaken to investigate the comparative physiological action of three elements, which are of equal valency and of approximately the same molecular weight, and whose chemical properties are closely related. The experiments were carried out in vitro and on unicellular organisms, bacteria and infusoria, frogs, pigeons, rats and guinea-pigs. The solutions used were the chlorids, isotonic with 0.6% sodium chlorid. In one case the propionate was used without any marked difference in the result being observed.

The chlorids coagulate egg and serum albumins, but neither the purified albumoses from Witte's peptone nor peptone are precipitated.

Dilute solutions delay the growth of bacteria and eventually kill. The solutions are not very toxic to spores. Opalina, para-mecia, and vorticellae are killed quickly, equivalent solutions of the chlorids acting in the following order of strength: Neodymium, prseseodymium and lanthanum.

In frogs voluntary and involuntary muscle are quickly put out of action. This is particularly the case with perfused muscle. The solutions act in the same order as with unicellular organisms. Intravenous injection causes almost instant death, due to multiple embolism.

Attempted chronic poisoning was unsatisfactory. The solutions were introduced both subcutaneously and intraperitoneally. Some of the animals died with ill-defined symptoms. Others remained well, except for areas of induration at the seat of injection. Experiments with oral administration and on elimination will be conducted.

As all the solutions, owing to hydrolysis, are acid in reaction, the authors are inclined to attribute a large share of the acute effects to the acid present. The salts range themselves in their toxicity according to their molecular weights.