(From Bolus 1455 a mass, from the Hebrew term balah, to agglutinate). A dole or bolus. Boluses differ not from electuaries, only they are made of a firmer consistence, in single doses, and therefore more proper where accuracy is required in the administration, and where evaporation would injure the medicine. The light and ponderous powders may more conveniently be mixed with mucilage, for so they are the least bulky. The quantity of each is as much as can be conveniently swallowed at once. The more disagreeable powders should be given in another form, and the more bulky doses mixed in draughts. This form is, however, now little employed, and the powders are usually mixed in draughts. Where swallowing is difficult, boluses are often improper. Yet we once saw 3ss. of valerian ordered in a bolus for a man in an apoplexy, by a fashionable physician.

Boll's, bole. Boles arc argillaceous earths, which readily fall clown into a loose mass in water; smooth, and rather unctuous to the touch. It is the argilla bolus of mineralogists; and, like other reputed argillaceous earths, contains the largest proportion of flint. Boles were once highly prized; and the Armenian and Lem-nian boles were dug and sealed with numerous ceremonies. They were accounted cordial, alexipharmic, and sudorific; and, in imitation of these, other argillaceous and calcareous earths were sold under the title of terra sigillatae, because they had, like the two former boles, the impression of a seal. They are all now neglected | yet, were we to interpose against authority, we would whisper some defence of the former, pulvis e bolo cum opio, now the pulv. e creta compositus cum opio.

Bolus gallicus, French bole, is a friable earthy substance of the argillaceous kind, intimately blended with a slight portion-of ferrugineous calx, and siliceous earth. It is of a pale red colour, variegated with irregular specks, and veins of a whitish yellow. It is said to imbibe sharp acrid humours, and has been recommended in alvine fluxes and cardialgia, in doses of from ten to sixty grains. Pipe clay, coloured with red chalk, is its very innocent substitute. Its sudorific and alexipharmic powers have no foundation.

There arc various other species that are not allowed to possess any medical virtues. The London college have consequently exchanged two compositions under the titles of pulvis e bolo compositus, sine opio et cum opio, for the pulvis e creta compositus, without and with opium. In the former, half a pound of prepared chalk is added to four ounces of cinnamon, three ounces of tormentil root, and as much gum arabic. In the latter, eight ounces of this powder are mixed with a drachm and half of powdered opium. Thus, about two scruples of the powder contain a grain of opium.