i6 II. THE JOURNEY 
x\t my request he spared me two hours every morning, 
during which he gave me an account of the general 
system of tropical medicine, illustrated by his own 
experiments and experiences. It was very necessary, 
he thought, that as many independent 'doctors as 
possible should devote themselves to the care of the 
native population ; only so could we hope to get the 
mastery of the sleeping sickness. 
The day after we left Teneriffe the troops were ordered 
to wear their sun-helmets whenever they were outside 
the saloons and cabins. This precaution struck me as 
noticeable, because the weather was still cool and fresh, 
hardly warmer than it is with us in June, but on the 
same day I got a warning from an “ old African,” as I 
was enjoying the sight of the sunset with nothing on my 
head. “ From to-day onwards,” he said, “ you must, 
even though the weather is not yet hot, regard the sun 
as your worst enemy, and that whether it is rising, or 
high in heaven, or setting, and whether the sky is 
cloudy or not. Why this is so, and on what the sun’s 
power depends, I cannot tell you, but you may take it 
from me that people get dangerous sunstrokes before 
they get close to the equator, and that the apparently 
mild heat of the idsing or setting sun is even more 
treacherous than the full glow of that fiery body at 
mid-day.” 
At Dakar, the great harbour of the Colony of 
Senegambia, my wife and I set foot for the first time 
on the soil of Africa to which we were to devote our 
lives, and we felt it as a somewhat solemn moment. 
Of Dakar itself I have no kindly remembrance, for I 
cannot forget the cruelty to animals which is universal 
there. The town lies on a steep slope, the streets are 
