56 (120) Society for Experimental Biology and Medicine. 



24 (70). " A preliminary study of the toxicological action of 

 thorium": ARTHUR F. CHACE and WILLIAM J. GlES. 



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 announce- 

 ment 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 con- 

 nective 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 ^//zNaCl, with fertilized Fundulus 

 eggs as the indicators. At that time we observed a strong pre- 

 cipitative 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 pre- 

 cipitation, 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. 



1 We have already reported our observations on the toxicology of tellurium ( 1 900) 

 and of selenium (1902). Effects of radium are indicated on page S6 (150). 



