FROM THE ATBARA TO WAD HAMED 95 sleeves or went to sleep well under cover of his canvas. Outside the sun blazed down in fury on the desert, till the rocks became too hot to be touched, and the rarefied air quivered over the yellow sand. To walk twenty yards in the open without a helmet might mean death, and even inside one’s tent the heat which penetrated a double roof of thick green canvas was so intense that a wet towel was very welcome as a protection for the head. Whenever the surrounding temperature exceeds that of the surface of one’s body there is always a risk of sunstroke, and it is amazing that during the heat which has prevailed in England during August and September few people took the trouble to protect their heads by any additional covering beyond a straw hat. In fact, Surgeon-Major Parkes states that he had come across many more cases of sunstroke in England than in Africa, where he had spent many years amid the vicissitudes of travel and exploration. Furthermore, a “spinal pad” is almost of as much importance as a good helmet against sunstroke, yet in the Sudan the use of the spinal pad supplied by the Government was