The gum-bearing mimosas are, on an average, I should say, about twenty-five feet high. The boles are straight. Thorns grow thickly on the branches. The white bark gives a characteristic and almost haunting feature to the great forest. The gum exudes, chiefly, at the junction of the branches with the trunk. Its appearance has been excellently described by Sir Samuel Baker: “At this season the gum was in perfection, and the finest quality was now before us in beautiful amber-coloured masses upon the stems and branches, varying from the size of a nutmeg to that of an orange. . . . This gum, although as hard as ice on the exterior, was limpid in the centre, resembling melted amber, and as clear as though refined by some artificial process. . . . The beautiful balls of frosted yellow gum recalled the idea of the precious jewels upon the trees in the garden of the wonderful lamp of the ‘Arabian Nights.’ The gum was exceedingly sweet and pleasant to the taste.”[17] The trees were in flower when we saw them, and the blossoms scented the air sweetly. The present method of collecting gum is primitive and unsystematic. Natives go a two or three days’ journey from Gedaref into the forest, when they are pressed by want of a commodity to sell or exchange, and return with as much as they have gathered at hazard. [Illustration: GUM BEARING MIMOSA TREES. _See p._ 30.] [Illustration: TRYING THE TEMPERATURE OF A PATIENT AT THE DOCTOR’S PARADE. _See p._ 115.] Throughout the day’s march we had seen fires raging in the dried grass, and we had frequently passed places where the charred surface showed the effect of the flames. The custom of setting the undergrowth alight would destroy the mimosa forest, but for the fact that the fires burn low and travel quickly. The branches of the trees do not spring from the lower expanse of the boles, and there is consequently no combustion of the timber, except where a quantity of old, sapless wood is ignited. Trouble threatened us at Shisana well. Grain for the donkeys and boys, that were to accompany us into Abyssinia, had been packed in sacks at Gedaref. The friction caused by the camels’ movement had frayed these open, and the grain was lying on the ground when we arrived. At first we feared that we should be obliged to return to the town and purchase new sacks; but luckily the camel-men were bringing with them a stock of capacious and pliable baskets, made of slit palm-leaves, which they had intended to sell at Gallabat. These we commandeered, and so extricated ourselves from the difficulty. Our journey next day was through entirely similar scenery, over undulating, rocky ground. We saw some ariel, but again they were too shy for us. Then we “declined upon” guinea-fowl, and bagged two after a brisk, exciting run.