In Storer's experiments on feeding rats with barium carbonate it was found that the barium carbonate would kill them, but if calcium carbonate was mixed with the barium the rats survived, suggesting an antidotal action. This apparent antagonism deserves further study and may lead to practical results.[230] A somewhat similar antagonism for at least a part of the action of barium has been claimed to exist between barium and potassium.[231] However, extracts of ashed plants, treated with acetic acid, which contained calcium and potassium, caused death in the experiments of the writer, but no work has yet been done by him as to the antidotal action of calcium carbonate on barium. Then, too, as Lüdeking[232] pointed out, large quantities of calcium chlorid may interfere with the precipitation of barium as a sulphate. It is well known that the presence of various salts influences the solubility of barium sulphate in water,[233] and the fact that barium has been found in solution in the urine in the presence of sulphates shows that the precipitation of barium as a sulphate in the body is not so simple as in test-tube experiments.[234] Again, in very dilute solutions, such as must necessarily occur at any one time in the stomach, the precipitate with sulphates only slowly forms and the barium may be absorbed before the insoluble compound can be formed.[235] Evidently an important point to be considered in the antidotal treatment of locoed animals with sulphates is the possibility of inducing a gastritis, with its attendant loss of weight. It therefore seems apparent that the proper treatment at present is preventive--that is, removal from the plants. Lewin[236] has suggested the possibility of acquiring some immunity to barium, but our experiments point against the production of any practical immunity. * * * * * FOOTNOTES: [228] Mendel, L. B., and Sicher, D. F., l. c., p. 148. [229] Mayo, N. S. Some Observations upon Loco. Kans. State Agric. Coll. Bul. 35, p. 119. 1893. [230] Storer, F. H. Experiments on Feeding Mice with Painter's Putty and with Other Mixtures of Pigments and Oils. Bul. of Bussey Institute, vol. 2, p. 274. 1884. [231] Brunton, T. L., and Cash, J. T. Contribution to Our Knowledge of the Connection between Chemical Constitution, Physiological Action, and Antagonism. Philos. Trans. Royal Soc. London, I, vol. 175, p. 229. 1884. [232] Lüdeking, C. Analyse d. Barytgruppe. Zeits. f. Anal. Chem., vol. 29, p. 556. 1890. [233] Fraps, G. S. Solubility of Barium Sulphate in Ferric Chloride, Aluminum Chloride, and Magnesium Chloride. Amer. Chem. Journ., vol. 27, p. 288. 1902. [234] Santi has paid special attention to the solubility of barium in the body. [235] Fresenius, C. G. Man. of Qualitat. Chem. Anal. Tr. by H. L. Wells, 1904, p. 148. [236] Lewin, L. Nebenwirkungen d. Arzneimittel, 2 ed., p. 439. 1893.