These are intimate mixtures of substances with sugar of milk. Each contains 10 per cent, of the active substance. A general formula for their preparation is given in the U.S.P., although only one is named. According to this formula 10 parts of the substance and 90 parts of sugar of milk are to be weighed out separately. The substance, reduced to a moderately fine powder if necessary, is mixed in a mortar with about its own bulk of sugar of milk, and they are triturated together. Fresh portions of the sugar of milk are added from time to time until the whole has been added, and the trituration is continued until the substance is intimately mixed with the sugar of milk and finely comminuted.