After a light lunch about 12.30, everybody, soldier and civilian alike, lolled about in shirt-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 rather the exception than the rule, and men walked about in the tropical sun with a helmet on their heads while their back was protected only by a flannel shirt. Sunstroke acts in different ways. I have seen the quartermaster of a P. and O. in the Red Sea suddenly drop as if he had been shot; but, in most cases, the initial stages--loss of appetite, nausea, and headache--give one full warning, and if the patient can at once get under some shade and secure medical assistance, the "touch of the sun," which has upset him for the time being, passes away without leaving any effects behind it except a general lassitude for some time. About four o'clock the hottest part was over, but the danger of sunstroke was, if anything, greater, because the oblique rays of the sun fell upon one's neck, unless, indeed, as was the case with the rank and file, a "curtain" was attached to the helmet. Nearly everybody drank tea about this time. There is a kind of notion abroad that this beverage serves to cool one, but the general effect produced in the Sudan seemed quite the reverse. Any perspiration left in one's sebaceous follicles after the genial warmth of the Sudan had kept us in a sort of natural Turkish bath for six hours, was elicited by the warm tea, and one realised how easy under such conditions it would be to lose every particle of one's existing body in even less than the seven years indicated by medical statistics, and thus, on good Bishop Butler's showing, secure, together with revaccination, a frequently recurring proof of one's immortality.