e locust in all
the coasts of Egypt."

Every person is aware that unwholesome air is quite poisonous to the
human system as impure water; and seeing that the noxious qualities of
the latter are caused by animalcules, and that the method used for
purifying infected air are those most generally destructive to insect
life, it is not irrational to conclude that the poisonous qualities of
bad water and bad air arise from the same cause.

Man is being constantly preyed upon by insects; and were it not for
ordinary cleanliness, he would become a mass of vermin; even this does
not protect him from the rapacity of ticks, mosquitoes, fleas and many
others. Intestinal worms feed on him within, and, unseen, use their
slow efforts for his destruction.

The knowledge of so many classes which actually prey upon the human
system naturally leads to the belief that many others endowed with the
same propensities exist, of which we have at present no conception.
Thus, different infectious disorders might proceed from peculiar
species of animalcules, which, at given periods, are wafted into
certain countries, carrying pestilence and death in their invisible
course.

A curious phenomenon has recently occurred at Mauritus, where that
terrible scourge, the cholera, has been raging with desolating effect.

There is a bird in that island called the "martin," but it is more
property the "mina." This bird is about the size of the starling, whose
habits its possesses in a great degree. It exists in immense numbers,
and is a grand destroyer of all insects. On this account it is seldom
or never shot at, especially as it is a great comforter to all cattle,
whose hides it entirely cleans from ticks and other vermin, remaining
for many hours perched upon the back of one animal, while its bill is
actively employed in searching out and destroying every insect.

During the prevalence of the cholera at Mauritius these birds
disappeared. Such a circumstance had never before occurred, and the
real cause of their departure is still a mystery.

May it not have been, that some species of insect upon which they fed
had likewise migrated, and that certain noxious animalcules, which had
been kept down by this class, had thus multiplied within the atmosphere
until their numbers caused disease? All suppositions on such a subject
must, however, remain in obscurity, as no proof can be adduced of their
correctness. The time may arrive when science may succe