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and in that time over twenty trout were sucked dry and their lifeless bodies sent floating away with the current. From this observation, I am satisfied that great numbers of trout, and perhaps infant fish ot other varieties in clear waters, must come to their death in this way.” Mr. Theobald has observed a small blood-sucking fly, Simuliwm reptans, settled on the bodies of roach while these were lying on water-plants in shoals during the spawning season.

Turning ‘now to the fish of the African rivers and lakes, we find that the suggestion of an association between tsetse flies and fish is supported by the peculiar habits of various fish belonging to the great family of Siluride, which, according to Mr. Boulenger,” is repre- sented in Africa by twenty-nine genera comprising no less than a hundred species. The Siluroids are charac- terised by having a naked skin and two or more long feelers or barbels oneach side of the mouth. The genera Synodontis and Clarias are of special interest to us; they are found very abundantly all over tropical Africa. The siluroids of the genus, Synodontis have the curious habit of swimming on their backs with the belly above the surface of the water as if they were dead. In one species (S. membranaceus) this habit appears to have brought about a reversion of the coloration, which is dark on the abdomen and light on the back. ‘The fish belonging to this genus can lead an amphibious life, and it is stated that occasionally they feed on grain. Even more interesting are the siluroids of the genus Clarias. During the dry season, when there is no longer any water in the meres they inhabit, the Clarias live in burrows, like rabbits, coming out towards evening in quest of food. The flesh of the Olarias is much ‘esteemed by the natives, and the women go and dig them out of their burrows.

Fish is an important article of food throughout tropical Africa, not only amongst the riverside popu- lations, but also amongst the inland tribes which barter it with’ manioc, bananas, or charcoal. The fish is usually parboiled in palm oil, and eaten with baked manioc leaves. Much of it is smoked, then kept in baskets and eaten raw.

Having thus hinted to a possible connection between fish and tsetse flies, I will draw attention to the fact that trypanosomes are very common parasites amongst fish. They have been found chiefly in freshwater fish, but quite recently Laveran and Mesnil™ found them in

soles (Solea vulgaris) and rays (Raja punctata and ros mosaica) from the British Channel. Lingard, who examined the freshwater fish of India, states that trypanosomes are especially common amongst those species which live in the mud. It is also important to remark with Laveran and Mesnil that the trypano- somes of fish are strikingly like those of mammals, and very different from those of the closer related Batrachians.

• Lastly, to connect the above observations with sleep-

ing sickness, I will point out that the natives of various parts of Africa believe ‘fish to be the cause of the dread disease. Thus, while the Sussus or Sossé (south of the Pongo river) ascribe sleeping sickness to the sting of a fish, the Congo negroes believe it to be due to the consumption of diseased fish with swollen gills.

THE JOURNAL OF TROPICAL MEDICINE. eee

[July 1, 1903.

Another theory somewhat prevalent amongst natives is that infection takes place by means of the saliva of the patient. They always eat with their hands out of the same family dish and lick their fingers after each mouthful. A similar theory is held with regard to nagana, the diseased animals are supposed to con- taminate the grass or drinking water by their saliva. This mode of infection is also in accordance with the trypanosoma theory of sleeping sickness, because we know that dourine can be acquired by direct contact with the secretions of the cedematous genital mucose. But, in sleeping sickness, direct contact is certainly not the usual means of transmission. On the other hand, dourine is probably also inoculated by blood- sucking insects.

In sleeping sickness the glands most frequently enlarged are those of the neck. In connection with this, | it is interesting to’remark that it is precisely on the neck and behind the back between the shoulders that | the fly most frequently bites man. Of course it may — bite any exposed part, and the naked legs of the natives — are frequently assailed. Horses and cattle are some- — times bitten on the back, but preferably inside the thighs, beneath the belly or below the tail. The tsetse darts suddenly on its hosts, making a loud buzzing noise. Its flight is rapid and straight. The tsetse will bite at any time, but (according to Bruce) preferably at sun-— set. It is known to bite by moonlight. In man the | bite causes a sharp prick which draws one’s attention suddenly to the spot, but the pain is trifling and the | subsequent swelling and irritation very slight.

PREVENTION.

I fear that for the present in sleeping sickness lazpos’ Yara: @avaros. The physician that cures is death. | Numerous remedies have been tried, but they were suggested by erroneous theories, and proved invariably useless. The natives have no better treatment; they administer cathartics and diaphoretics, but in early cases they sometimes extirpate or cauterise the swollen glands to prevent the further progress of the disease. This bold surgical interference is common to various populations in West Africa and deserves investigation.

In 1873, in aletter to Dr. J. W. Ogle, Dr. MW Carthy,” Assistant Surgeon at Accra, says: “In every case of ‘ sleeping sickness ’ there is invariably a chronic thicken- ing of the deep cervical glands of the neck. I mean those glands commonly called the * glandula conca~ tenata, and which form a chain from the base of the skull to the clavicle. The treatment adopted by the native ‘doctors’ consists in removing these thickened glands. I have never seen the operation performed, but it is said to be always followed by cure. In one man I counted no less than thirteen cicatrices in the neck.”

Surgeon-Major Gore says: “I had just returned from shooting, when a native was brought to my bunga- low with an enlargement of the glands of the neck which he was anxious to have removed. My servant, @ Portuguese, informed me that he stated he was afraid he was about to get the ‘sleeping sickness.’ Upo further inquiry I found that this was really the case and that among the people of the neighbourhooe