DOWN THE CONGO TO THE ATLANTIC. 
443 
tropics seems nowadays almost superfluous ; it is so well 
understood that in these humid shades the earth seethes 
with life, that in these undrained recesses the primitive 
laboratory of nature is located, for disturbing which the 
unacclimatized will have to pay the bitter penalty of 
malarial fever. 
One hears much about “ the silence of the forest ” — 
but the tropical forest is not silent to the keen observer. 
The hum and murmur of hundreds of busy insect tribes 
make populous the twilight shadows that reign under 
the primeval growth. I 
hear the grinding; of 
O O 
millions of mandibles, 
the furious hiss of a tribe 
just alarmed or about to 
rush to battle, millions 
of tiny wings rustling 
through the nether air, 
the march of an insect 
tribe under the leaves, 
the startling leap of an 
awakened mantis, the 
chirp of some eager and 
garrulous cricket, the 
buzz of an ant-lion, the 
roar of a bull-frog. Add 
to these the crackle of 
twigs, the fall of leaves, 
the dropping of nut and 
berry, the occasional crash of a branch, or the con- 
stant creaking and swaying of the forest tops as the 
strong wind brushes them or the gentle breezes awake 
them to whispers. Though one were blind and alone 
in the midst of a real tropical forest, one’s sense of 
hearing would be painfully alive to the fact that an 
incredible number of minute industries, whose number 
one could never hope to estimate, were active in the 
shades. Silence is impossible in a tropical forest. 
About ten o’clock, as we cowered in most miserable 
condition under the rude, leafy shelters we had hastily 
