384 REPORT OF THE HARVARD AFRICAN EXPEDITION 
One case had enlarged glands in the neck. In the other cases, the glands were 
palpable but very small. Several of these prisoners were in poor condition and 
appeared slightly somnolent. 
In a case at the dispensary near the White Father’s Mission where the sleep- 
ing sickness cases of the district are collected, the gland puncture specimen 
which we examined contained exceedingly few trypanosomes. There were but 
twenty patients undergoing treatment at the lazaretto. 
The entire Semliki Valley between Lakes Albert and Edward, we found, 
had been almost entirely evacuated on account of the previous ravages of sleep- 
ing sickness, though the Belgian officials told us that certain wild tribes continued 
to live there in small bands in spite of all their efforts to evacuate the population. 
It is said that during the last few years the population of the southern half of 
this very fertile valley has been decimated by the disease. Most of the recent 
cases of sleeping sickness coming from this region have been collected in the 
lazaretto in the neighborhood of New Beni, referred to above. The Belgian 
officials believed that most of the cases of trypanosomiasis treated at New Beni 
occurred in persons who had previously lived in the Semliki Valley. Trypano- 
somiasis was certainly not developing to any great extent at New Beni, as far 
as is known, and could be ascertained at the time of our visit, though it has been 
feared that the disease may gain a footing in spite of the altitude. 
We examined a few cases in the Semliki Valley itself that were suspected of 
being infected but found no trypanosomes. Also, we were surprised at the 
relatively very few tsetse flies observed in this locality. In the Semliki Valley 
as well as in the Ituri Forest, the only tsetse flies that we collected were on the 
elephants or buffalo we recently shot. Such game and wart hogs were plentiful. 
Hippopotomuses were also observed in the Semliki River, but no crocodiles were 
seen. (For routes followed see Maps V and VI.) 
The epidemiology of sleeping sickness was investigated recently by the League 
of Nations Sleeping Sickness Commission, particularly in the Semliki Valley, 
the Upper Uele and in Budama and Kavirondo. They concluded that regarding 
the Upper Uele District as a whole it was apparent that the efforts of the medical 
service during the last three years had been crowned with success and that the 
disease was abating. However, they regard the endemic area in the Semliki 
Valley as serious,' the virus showing a tendency to spread and create fresh foci of 
infection in the Glossina palpalis distribution area. They further point out that 
in this area the natives possess no safeguard against infection but will, on the 
contrary, be the first to spread the disease by reason of their migratory habits 
and racial ties. 
During 1927 Doctors Van Hoof and Lavier journeyed from Irumu to New 
Beni and through the lower portion of the Semliki Valley, following the lower 
spurs of the Mitumba Mountains as far as Lake Edward. Van Hoof points out 
that it would be quite possible for an unsuspecting traveller to follow this route 
without noticing Glossina, but that nevertheless G. palpalis exists everywhere 
on all the rivers. A number of Glossina that he found were dissected, but no 
' See particularly Van Hoof and Lavier, loc. cit., p. 329. 
