Abstract
Thallium sulphate administered by mouth to quail, geese and ducks has been found to be fatally toxic in doses of 12, 15, and 30 mg. per Kg. respectively, calculated as thallium metal. Analyses were made of the distribution of thallium in various body tissues by a gravimetric iodide method, and by a new colorimetric method involving liberation of iodine from potassium iodide by thallium, and the estimation of the color intensity of the iodine in carbon bisulphide. The latter method is accurate to within 5% at a thallium concentration of 15 mg. per Kg. Thallium in liver, kidney, heart, and osseous tissue was estimated to be present in a concentration approximately equal to that which had been administered. Muscular tissue, however, was found to acquire a considerable higher concentration of thallium. Fat was found to contain practically none. Analysis of the tissues of a goose dying 15 days after the oral administration of 20 mg. per Kg. indicated a retention of 35-70% of the thallium given.
The first studies on the excretion of thallium were reported in 1890 by James Blake, 1 a physician residing in Middletown, California, who found by spectroscopic examination that thallium was eliminated in all secretions. Quantitative estimations of the rate of elimination of thallium in the urine after oral administration to dogs, by the colorimetric method noted above, indicated that 60% of the total amount given was excreted in 36 days, with a progressive diminishing rate of excretion.
Although thallium is very slowly excreted, and although the edible tissue of birds seems to retain a relatively large amount of ingested thallium there would seem to be no great danger that secondary poisoning in man might result from the eating of game birds poisoned with thallium, since a relatively large amount of such flesh would be necessary to contain a toxic dose of thallium for man.
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