[[2]] I must, however, in justice add that the mosquito does not harbour the trypanosomes permanently, and that its saliva is poisonous only for a short time after it has been polluted by the blood of a sleeping sickness victim.
In its essential nature sleeping sickness is a chronic inflammation of the meninges and the brain, one, however, which always ends in death, and this ensues because the trypanosomes pass from the blood into the cerebro-spinal fluid. To fight the disease successfully it is necessary to kill them before they have passed from the blood, since it is only in the blood that atoxyl,[[3]] one weapon that we at present possess, produces effects which can to any extent be relied on; in the cerebro-spinal marrow the trypanosomes are comparatively safe from it. A doctor must, therefore, learn to recognise the disease in the early stage, when it first produces fever. If he can do that, there is a prospect of recovery.
[[3]] Atoxyl (meta-arsenic anilid) is a compound of arsenic with an aniline product.
In a district, therefore, where sleeping sickness has to be treated, its diagnosis is a terribly complicated business because the significance of every attack of fever, of every persistent headache, of every prolonged attack of sleeplessness, and of all rheumatic pains must be gauged with the help of the microscope. Moreover, this examination of the blood is, unfortunately, by no means simple, but takes a great deal of time, for it is only very seldom that these pale, thin parasites, about one eighteen-thousandth (1/18000) of a millimetre long, are to be found in any considerable number in the blood. So far I have only examined one case in which three or four were to be seen together. Even when the disease is certainly present one can, as a rule, examine several drops of blood one after another before discovering a single trypanosome, and to scrutinise each drop properly needs at least ten minutes. I may, therefore, spend an hour over the blood of a suspected victim, examining four or five drops without finding anything, and even then have no right to say there is no disease; there is still a long and tedious testing process which must be applied. This consists in taking ten cubic centimetres of blood from a vein in one of the sufferer's arms, and keeping it revolving centrifugally for an hour according to certain prescribed rules, at the same time pouring off at intervals the outer rings of blood. The trypanosomes are expected to have collected into the last few drops, and these are put under the microscope; but even if there is again a negative result, it is not safe to say that the disease is not present. If there are no trypanosomes to-day, I may find them ten days hence, and if I have discovered some to-day, there may be none in three days' time and for a considerable period after that. A white official, whose blood I had proved to contain trypanosomes, was subsequently kept under observation for weeks, in Libreville, without any being discovered, and it was only in the Sleeping Sickness Institute at Brazzaville that they were a second time proved to be there.
If, then, I wish to treat such patients conscientiously, a couple of them together can tie me for a whole morning to the microscope, while outside there are sitting a score of sick people who want to be seen before dinner-time! There are also surgical patients whose dressings must be renewed; water must be distilled, and medicines prepared; sores must be cleansed, and there are teeth to be drawn! With this continual drive, and the impatience of the waiting sick, I often get so worried and nervous that I hardly know where I am or what I am doing.
Atoxyl is a frightfully dangerous drug. If the solution is left for some time in the light it decomposes, just like salvarsan, and works as a poison, but even if it is prepared faultlessly and is in perfect condition, it may cause blindness by injuring the nerves of sight. Nor does this depend on the size of the dose; small ones are often more dangerous than large ones, and they are never of any use. If one begins with too small a dose, in order to see whether the patient can take the drug, the trypanosomes get inured to it; they become "atoxyl-proof," as it is called, and then can defy the strongest doses. Every five days my sleeping sick come to me for an injection, and before I begin I always ask in trepidation whether any of them have noticed that their sight is not as good as usual. Happily, I have so far only one case of blinding to record, and that was a man in whom the disease had already reached a very advanced stage. Sleeping sickness now prevails from the east coast of Africa right to the west, and from the Niger in the north-west to the Zambesi in the south-east. Shall we now conquer it? A systematic campaign against it over this wide district would need many doctors and the cost would be enormous.... Yet, where death already stalks about as conqueror, the European States provide in most niggardly fashion the means of stopping it, and merely undertake stupid defensive measures which only give it a chance of reaping a fresh harvest in Europe itself.
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After the sleeping sickness it is the treatment of sores and ulcers which takes up most time. They are far more common here than in Europe—one in four of the children in our school has a permanent sore. What is the cause?
Sandfleas, crawcraw, raspberry disease, etc.
Many sores are caused by sandfleas (Rynchoprion penetrans), a species much smaller than the common flea. The female bores into the tenderest part of the toe, preferably under the nail, and grows under the skin to the size of a small lentil. The removal of the insect causes a small wound, and if this gets infected through dirt, there sets in a kind of gangrene, which causes the loss of a joint, or even of a whole toe. Negroes with ten complete toes are almost rarer than those who have one or more mutilated.