Gum Arabic The purest and finest gum arabic is brought in caravans to Cairo, by the Arabs of the country round Mounts Tor and Sinai, who bring it from this distance on the backs of camels, sewn up in bags, and often adulterated with sand, etc. The gum exudes spontaneously from the bark and trunk of the branches of the tree, in a soft, nearly fluid state, and hardens by exposure to the air, or heat of the sun. It begins to flow in December, immediately after the rainy season, near the flowering time of the tree. Afterwards, as the weather becomes hotter, incisions a;e made through the bark, to assist the transudation of the juice.