SERVANTS OPHTHALMIA . 
171 
Mohammed Tunisee has done him great harm; 
but, nevertheless, this chap continues to improve 
since the arrangement made, by which he becomes 
only the servant of Barth. The Germans, however, 
are still afraid of him. Yusuf is trying the same 
system with me, but will probably find that it will 
end in no good affair for himself. Mohammed Tunisee 
and Yusuf seem hitherto to have combined to spoil 
all our people. The liberated slaves from Tunis, 
brought up by me, have turned out the best and 
most faithful servants. I am much pleased with 
this. 
All the people of Damerghou are afflicted with 
ophthalmia, which is said to arise from the winds 
that prevail constantly over this open and unsheltered 
country. Some of the people pretend it is caused by 
drinking ghaseb-water, which appears absurd enough. 
The Moorish and other merchants attribute the 
greater part of their diseases to drinking water, — 
especially the fevers. How much truth there is in 
this assertion is not easy to be determined. 
11th. — It has been agreed that I and my col- 
leagues should here part for a time, Dr. Barth going 
to Kanou, and Dr. Overweg to Tesaoua and Mara- 
dee, whilst I proceed with En-Noor direct to Zinder. 
Dr. Barth promises to be in Kuka in two months ; 
and Dr. Overweg says he will immediately corre- 
spond, that is from Tesaoua to Zinder. The latter 
has the more difficult journey before him ; but even 
Dr. Barth's visit to Kanou may turn out a more 
