Absorption by the skin is not so dangerous as has been believed. Rossignol has shown that poisoning need not be feared in chemical baths unless the proportion of dissolved arsenic is above 150 grains per quart, especially if the period of immersion does not exceed five minutes. Even pure solutions of arsenic, free from any astringent, may be used, provided the quantity in the bath does not exceed 120 grains per quart.
The bath should, if possible, be kept warm—85° to 95° Fahr. (30° to 35° C.).
Four men are generally employed for the operation. One drives in the sheep, two others hold and brush them in the bath, and the fourth holds the head of the animal above the liquid. Tessier recommended gloves for the use of the operators, but experience has shown that such a precaution is unnecessary. The udder, and particularly the teats, of ewes with young may, if necessary, be smeared with some fatty substance, such as vaseline or oil, in order to guard against the astringent action of the liquid.
Each sheep is plunged in the bath for one or two minutes, or five minutes at the most. All the diseased spots must be brushed, rubbed and cleansed; but care must be taken not to make them bleed.
Tessier suggested leaving the animals for twenty-four hours in some disinfected place, without straw or food, to prevent these materials from being wetted by the liquid which runs from the fleece, and which, if afterwards eaten, might have a poisonous effect. Here, again, the danger has been exaggerated. Delafond has shown that sheep may be given a fluid ounce of Tessier’s bath for eight days running without producing the slightest unfavourable symptom.
Tessier’s bath is excellent from the therapeutic standpoint, but it imparts a yellow tint to the fleece, which is thus rendered less valuable. The mixture has therefore been modified in various ways.
Clément’s Bath (1846).
| For 100 sheep | Arsenious acid | 1·5 | parts or lbs. |
| Sulphate of zinc | 5 | „ | |
| Water | 100 | „ |
In this bath every quart contains about 2½ drachms of arsenious acid. Its toxic power, therefore, is considerably greater than that of Tessier’s bath.
Clément’s formula has one drawback. The sulphate of zinc may be mistaken for a non-astringent alkaline sulphate (sulphate of soda), and as a consequence poisoning may occur, as experience has shown.