The question is, therefore, reduced to the
prime cause of the disease itself.
A theory that animalcules are the cause of the various contagious
and infectious disorders has created much discussion; and
although this opinion is not generally entertained by the
faculty, the idea is so feasible, and so many rational arguments
can be brought forward in its support, that I cannot help
touching upon a topic so generally interesting.
In the first place, nearly all infectious diseases predominate in
localities which are hot, damp, swampy, abounding in stagnant
pools and excluded from a free circulation of air. In a tropical
country, a residence in such a situation would be certain death
to a human being, but the same locality will be found to swarm
with insects and reptiles of all classes.
Thus, what is inimical to human life is propitious to the insect
tribe. This is the first step in favor of the argument.
Therefore, whatever shall tend to increase the insect life must
in an inverse ratio war with human existence.
When we examine a drop of impure water, and discover by the
microscope the thousands of living beings which not only are
invisible to the naked eye, but some of whom are barely
discoverable even by the strongest magnifying power, it certainly
leads to the inference, that if one drop of impure fluid contains
countless atoms endowed with vitality, the same amount of impure
air may be equally tenanted with its myriads of invisible
inhabitants.
It is well known that different mixtures, which are at first pure
and apparently free from all insect life, will, in the course of
their fermentation and subsequent impurity, generate peculiar
species of animalcules. Thus all water and vegetable or animal
matter, in a state of stagnation and decay, gives birth to insect
life; likewise all substances of every denomination which are
subjected to putrid fermentation. Unclean sewers, filthy hovels,
unswept streets, unwashed clothes, are therefore breeders of
animalcules, many of which are perfectly visible without
microscopic aid.
Now, if some are discernible by the naked eye, and others are
detected in such varying sizes that some can only just be
distinguished by the most powerful lens, is it not rational to
conclude that the smallest discernible to human intelligence is
but the medium of a countless race? that millions of others still
exist, which are too minute for any observation?
Observe the particular quarters of a city which suffers most
severely during the prevalence of an epidemic, In all dirty,
narrow streets, where the inhabitants are naturally of a low and
uncleanly class, the cases will be tenfold. Thus, filth is
admitted to have at least the power of attracting disease, and we
know that it not only attracts, but generates animalcules;
therefore filth, insects and disease are ever to he seen closely
linked together.
Now, the common preventives against infection are such as are
peculiarly inimical to every kind of insect; camphor, chloride of
lime, tobacco-smoke, and powerful scents and smokes of any kind.
The first impulse on the appearance of an infectious disease is
to purify everything as much as possible, and by extra
cleanliness and fumigations to endeavor to arrest its progress.
The great purifier of Nature is a violent wind, which usually
terminates an epidemic immediately; this would naturally carry
before it all insect life with which the atmosphere might be
impregnated, and the disease disappears at the same moment. It
will he well remembered that the plague of locusts inflicted upon
Pharaoh was relieved in the same manner: "And the Lord turned a
mighty strong west wind, which took away the locusts and cast
them into the Red Sea; there remained not one 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.
