The occurrence of arsenic as an occasional constituent of plants has been recognised for many years. [Chatin (1845)] found that if a plant were supplied with arsenical compounds at the roots arsenic was absorbed, but that it was distributed unequally to the various tissues. The greatest accumulation of the element was in the floral receptacle and the leaves, while it was scarce in the fruits, seeds, stems, roots and petals. [E. Davy (1859)] commented on the presence of arsenic in plants cultivated for food. He grew peas in pots and watered them for a short time with a saturated aqueous solution of arsenious acid, the application being then discontinued. The plants, apparently uninjured by the treatment, flowered and formed seeds. On analysis arsenic was readily detected in all parts of the plant, including the seeds. Other analyses revealed the presence of the element in cabbage plants (from pots) and turnips (from field), both of which had been manured with superphosphate containing some amount of arsenic. This absorption of arsenic by the roots of plants was further established by [Phillips (1882)].
Various physiological workers have pointed out that this element is frequently or usually present in animal tissues. [Cerný (1901)] reached the general conclusion that minimal traces of arsenic can occur in animal organisms, but that these play no part in the organism and indeed are not constant in their occurrence. [Bertrand (1902)] established its presence in minute quantities in the thyroid glands of the ox and pig, hair and nails of the dog, and the feathers of the goose. [Gautier and Clausmann (1904)] realised the constant presence of arsenic in human tissues and recognised that it must inevitably be introduced into the body with the food. This led them to estimate the arsenic present in various animal and vegetable foods, some of their results being given in the following table.
Arsenic per 100 parts fresh substance in µ gr. (= thousandth part of a milligram)[8].
| Wheat | (Victoria—complete grain) | ·7 | |
| „ | (from Franche Comté) | ·85 | |
| White bread | ·71 | ||
| Whole green cabbage | ·2 | ||
| Outside leaves of cabbage | ·0 | (absent) | |
| Green haricots | ·0 | „ | |
| Turnip | ·36 | ||
| Potatoes | 1·12 | ||
Arsenic was also found in wine and beer and in considerable quantities in sea water and various kinds of salt. Since it cannot be found in some things even in the least traces, the authors conclude that it is incorrect to say that the element is always present or that it is essential to all living cells.
[S. H. Collins (1902)] found that barley is able to absorb relatively large quantities of arsenic. The plants were grown in pots on soil which originally contained a certain amount of the substance, and various combinations of arsenic acid, arsenious acid and superphosphate were added. Particulars and details are not given by the author, except that arsenic was detected by Reinsch’s test in the grains from all the experimental pots, and in one case (not specified) in the upper and lower halves of the straw and in the threshed ears. The analyses of the soil at the close of the experiments showed the presence of 7–22 parts arsenious acid per million.
[Wehmer (1911)] quotes references to the occurrence of arsenic in Vitis vinifera. The element was detected in the ash of the must and its presence was attributed to treatment of the plants with arsenical compounds. In this connection it is interesting to note the observation of [Swain and Harkins (1908)], who, while acknowledging the absorption of arsenic from the soil by many plants, yet indicate that in the case of those plants which are exposed to smelter smoke the arsenic is deposited on the vegetation, and is not absorbed by the latter from the soil.