s, there would probably be so great a falling off in
the yield and value of feathers in birds kept under artificial
conditions in England that the speculation would not be likely to pay."

"Do the hens sit on their eggs, as ordinary hens?"

"Just the same," Mr Harvey answered, "and very funny they look with
their long legs sticking out. Not only does the hen sit, but the cock
takes his turn at keeping the eggs warm when the mother goes out to
feed."

"I shall ask father," Dick said, "when we get back, to arrange to take
these fifteen ostriches as part of his share of the venture; it would be
great fun to see them stalking about."

"Ah! we have not got them home yet," Mr Harvey replied, smiling; "we
must not be too sanguine. We have certainly begun capitally, but there
is no saying what adventures are before us yet. We have been
particularly fortunate in seeing nothing of the tzetze fly. As you
know, we have made several considerable detours to avoid tracts of
country where they are known to prevail, still, occasionally they are
met with in unexpected places, and I have seldom made a trip without
losing some of my horses and cattle from them."

"How is it that a fly can kill a horse? They are not larger than our
blue-bottles at home, for I saw one in a naturalist's window in
Pieter-Maritzburg."

"It is a mystery, Dick, which has not yet been solved; there are flies
in other parts of the world, whose bite is sufficiently poisonous to
raise bumps underneath the skins of animals, but nothing approaching the
tzetze in virulence. It certainly appears unaccountable that the venom
of so small a creature should be able to kill a great animal like a
horse or an ox."

"Is it found only in the south of Africa?"

"No, Dick, it extends more or less over the whole of the plateau-lands
of Africa, and is almost as great a scourge in the highlands of Egypt as
it is here."

"I wonder," Dick said thoughtfully, "why the tzetze was created; most
insects are useful as scavengers, or to furnish food for birds, but I
cannot see the use of a fly which is so terribly destructive as this."

"I can't tell you, my boy," Mr Harvey said. "That everything, even the
tzetze has a good purpose, you may be sure, even though it is hidden
from us. Possibly, for example, it may be discovered some day that the
tzetze is an invaluable medicine for some disease to which man is
subject, just as blistering powder is obtained from the crest-body