air, enabling travellers to obtain water and even ice from the
atmosphere, are great aids in desert exploration, removing
absolutely the principal distress of the ancient caravan. The
erstwhile 'Dark Continent' has a larger white population now than
North America had a hundred years ago, and has this advantage for
the future, that it contains 11,600,000 square miles, while North
America has less than 9,000,000. Every part of the globe will
soon sustain about as large and prosperous a population as the
amount of energy it receives from the sun and other sources will
warrant; public debts and the efficiency of the governments being
the variable elements.

"The rabbits in Australia, and the far more objectionable
poisonous snakes in South America and India, have been
exterminated by the capture of a few dozen of the creatures in
the infested districts, their inoculation with the virus similar
to the murus tiphi, tuberculosis or any other contagious-germ
complaint to which the species treated was particularly
susceptible, and the release of these individuals when the
disease was seen to be taking hold. The rabbits and serpents
released at once returned to their old haunts, carrying the
plague far and wide. The unfortunate rabbits were greatly
commiserated even by the medicos that wielded the death-dealing
syringe; but, fortunately for themselves, they died easily. The
reptiles, perhaps on account of the wider distribution of the
nerve centres, had more lingering but not painful deaths, often,
while in articulo mortis, leaving the holes with which they
seemed to connect their discomfort, and making a final struggle
along the ground, only to die more quickly as a result of their
exertions. We have applied this also to the potato-bug, locust,