50 GENERAL ROUTINE WORK other nationalities. Of these, the Egyptians, the majority of them engaged in military service, are the most numerous. The Southern Sudan is the home of the negro tribes—the Dinkas, Shilluks, Nuers, Nyuaks, Niam-niams, and many others. It is hopeless with our present knowledge to proceed to any kind of a classification, and none will be attempted.

I. —Diseases Appearing from an Examination of the Blood Malaria (native name, humma==iQver).—All three forms of the malaria parasite have been seen. The most common have the benign tertian and the malignant tertian, the latter appearing as small ring forms and crescents. Quartan is rare and is probably acquired in Egypt or elsewhere, not in the Sudan. Cases from up the Niles, and especially from the White Nile, show the small ring and crescent forms most frequently. Typical ague attacks occur, but are not often seen. Remittent fevers seem to be the rule in the southern districts. Enlarged spleens due to malaria are numerous. Captain Cummins, E.M.C., found a large percentage of children in the Bahr-El-Ghazal affected in this way. A high per¬ centage of large mononuclear leucocytes is frequently found in the blood of natives, or Egyptian soldiers who have served up country. Very few cases have been seen in which such white corpuscles contained pigment. Chronic splenitis sometimes leads to a very considerable enlargement of the spleen. It will be interesting to see if the new blood parasite, Leishmania Donovani, is to be found in cases of splenomegaly. 1 Professor Ross has suggested to me that it might be well to look for it in monkeys.

Filariasis seems to be rare in the Northern Sudan, although Culex fatigans abounded in Khartoum before preventive measures were adopted. I have only seen one case of elephantiasis (da el feel). It was in the leg of a Dinka, but his blood showed no filaria embryos.

As Mansonia uniformis exists in considerable numbers along the banks of the Blue Nile, south of Wad Medani; in veritable swarms on the White Nile, south of Abbas Island, and all along the Sobat, Baro and Pibor Rivers and the reedy shores of Lake No, one would expect to find abundant evidence of filarial infection. Gross lesions, such as lymph scrotum, chylocele, varicose groin glands, and elephantiasis of the legs are not visible to the passing traveller even if he looks out for them. I had no opportunity of examining the blood of natives, nor, so far as I know, has any work been done on this subject in these regions.

1 rypanosomiasis has not been encountered. Trypanosomes possibly occur in the blood of natives living close to the more tropical parts of the White Nile. No trypanosomes were found in the blood of several siluroid fish examined.

Glossina palpalis has not been found in the Sudan. Glossina m,or sit arts occurs in the Bahr-El-Ghazal, and is numerous in some parts.

1 It has now been discovered in a single case at Omdurman by Dr. Sheffield Neave, vide B.M.J. 28/5/04