Having waited a month for the commencement of the healthy season at Kilimane, I would have started at the beginning of April, but tarried a few days in order that the moon might make her appearance, and enable me to take lunar observations on my way down the river. A sudden change of temperature happening on the 4th, simultaneously with the appearance of the new moon, the commandant and myself, with nearly every person in the house, were laid up with a severe attack of fever. I soon recovered by the use of my wonted remedies, but Major Sicard and his little boy were confined much longer. There was a general fall of 4 Deg. of temperature from the middle of March, 84 Deg. at 9 A.M., and 87 Deg. at 9 P.M.; the greatest heat being 90 Deg. at midday, and the lowest 81 Deg. at sunrise. It afforded me pleasure to attend the invalids in their sickness, though I was unable to show a tithe of the gratitude I felt for the commandant's increasing kindness. My quinine and other remedies were nearly all expended, and no fresh supply was to be found here, there being no doctors at Tete, and only one apothecary with the troops, whose stock of medicine was also small. The Portuguese, however, informed me that they had the cinchona bark growing in their country--that there was a little of it to be found at Tete--whole forests of it at Senna and near the delta of Kilimane. It seems quite a providential arrangement that the remedy for fever should be found in the greatest abundance where it is most needed. On seeing the leaves, I stated that it was not the 'Cinchona longifolia' from which it is supposed the quinine of commerce is extracted, but the name and properties of this bark made me imagine that it was a cinchonaceous tree. I could not get the flower, but when I went to Senna I tried to bring away a few small living trees with earth in a box. They, however, all died when we came to Kilimane. Failing in this mode of testing the point, I submitted a few leaves and seed-vessels to my friend, Dr. Hooker, who kindly informs me that they belong "apparently to an apocyneous plant, very nearly allied to the Malouetia Heudlotii (of Decaisne), a native of Senegambia." Dr. H. adds, "Various plants of this natural order are reputed powerful febrifuges, and some of them are said to equal the cinchona in their effects." It is called in the native tongue Kumbanzo.
The flowers are reported to be white. The pods are in pairs, a foot or fifteen inches in length, and contain a groove on their inner sides. The thick soft bark of the root is the part used by the natives; the Portuguese use that of the tree itself. I immediately began to use a decoction of the bark of the root, and my men found it so efficacious that they collected small quantities of it for themselves, and kept it in little bags for future use. Some of them said that they knew it in their own country, but I never happened to observe it. The decoction is given after the first paroxysm of the complaint is over. The Portuguese believe it to have the same effects as the quinine, and it may prove a substitute for that invaluable medicine.
There are numbers of other medicines in use among the natives, but I have always been obliged to regret want of time to ascertain which were useful and which of no value. We find a medicine in use by a tribe in one part of the country, and the same plant employed by a tribe a thousand miles distant. This surely must arise from some inherent virtue in the plant. The Boers under Potgeiter visited Delgoa Bay for the first time about ten years ago, in order to secure a port on the east coast for their republic. They had come from a part of the interior where the disease called croup occasionally prevails. There was no appearance of the disease among them at the period of their visit, but the Portuguese inhabitants of that bay found that they had left it among them, and several adults were cut off by a form of the complaint called 'Laryngismus stridulus', the disease of which the great Washington died. Similar cases have occurred in the South Sea Islands. Ships have left diseases from which no one on board was suffering at the time of their visit. Many of the inhabitants here were cut down, usually in three days from their first attack, until a native doctor adopted the plan of scratching the root of the tongue freely with a certain root, and giving a piece of it to be chewed. The cure may have been effected by the scarification only, but the Portuguese have the strongest faith in the virtues of the root, and always keep some of it within reach.