A resinous substance in the form of tears, of a pale yellow colour, and farinaceous appearance; having little smell and a bitter taste. It flows naturally from the tree; but this process is accelerated by making incisions in the bark. It is extensively used in the composition of varnishes. Pure alcohol and oil of turpentine dissolve it chiefly, the residue partaking of the nature of caoutchouc. An agreeable odour is given out by mastic when heated; it is, in consequence, much used in fumigations, and in the fabrication of. pastiles.