212. Olibanum: hot and dry in the second degree; it is the gum of a tree that is found in the city called Alexandria, and it is also found in the city called Damascus; it is best when clear in colour. It has the comforting and healing virtues, and it retains its efficacy for a long time when kept. If olibanum and mastix be mixed with wine and white of egg and applied to the temples and the forehead, it will stop the flow of the humours to the eyes and to the teeth. If it be held under the teeth, it will help with elongation of the uvula, and it will prevent the flow of the humours to the chest and to the lungs. If pills be made of the same gum, and five or four of them be given before going to bed, it will help with the acid eructation, and it will comfort the digestion. If the same gum be put on red coals, and the fumes allowed to the vagina, it will induce the foetus without