THE ARGUMENT DRAWN IN FAVOUR OF THE PROPAGATION OF DISEASE BY
ATMOSPHERIC CONTAGION, FROM DISEASE APPEARING IN PREVIOUSLY HEALTHY
HOUSES AND LOCALITIES TO WHICH PERSONS SICK, OR LATELY SO, HAVE BEEN
REMOVED.
A case of an apparently strong nature is made out in favour of the
propagation of disease by atmospheric contagion, when a person labouring
under sickness or lately recovered from it, is removed into a house or
locality in which the same malady shortly manifests itself. It is often
held conclusive; we hold it otherwise.
Such a case is known to take place, and we have observed it in our own
practice—but that is not entitled to be considered conclusive. It should
be shewn, if that inference is at all to be arrived at, that the
occurrence is so frequent that the probability is precluded of
attributing the phenomena observed to the ordinary causes of disease,
that the number who thus suffer is greatly more in proportion than holds
among the population generally, and that, in short, those thus visited
by the sick are affected in a greater ratio than holds with the general
community, as ascertained by an observation of the whole course of the
disease or epidemic.
We know that the appearance of disease among those visited by the
sick, or those lately recovered, does not always happen. We ourselves,
scarcely recovered of typhus fever, have visited and lived with a
family at a distance, and no such thing as propagation has
occurred—and hundreds of other cases are within our knowledge. We
have, after making calculations on the subject, considering both those
cases, where disease did occur and where it did not, that, generally
speaking, those visited by convalescents, or even patients, suffer in
a proportion very little greater, if at all greater, than those having
no such intercourse—compared of course with the very many cases that
are wont to occur in a widely spread epidemic.
Yet, though the general proportion may not be much affected, still we
are ready to admit that a case does now and then occur, where disease is
shortly observed after the admittance of a sick person in a house or
locality, and where the effect is so marked, so immediate and so general
among those exposed, that we are compelled to admit that there is room
for thinking, that the patient is somehow or other, in some degree at
least, the occasion of the catastrophe.
It is sometimes observed that servant girls, affected with typhus fever,
are in that state sent to their homes, and that disease shortly affects
their brothers and sisters, but before such cases can be held as proving
the existence of atmospheric contagion, there should be a strong
assurance that the agencies of a most unwholesome character, known to
exist in such cases, are inert, and that they which have on other
occasions, without assistance, produced of themselves the distemper
observed, have been altogether impotent and inactive.
Their case produces the usual effect, demands the exertion of night
watching, spoken of already, as favourable to the accession of disease,
and their house or apartment, close and confined as it usually is in
that rank of life, becomes the abode of many unwholesome influences, and
among others, of an atmosphere, deprived in a great degree of its more
essential part, and loaded, too, with foreign gases, and even perhaps
with chemical compounds of a virulent character, the products of
putrefaction. If disease spreads much among those thus exposed, it seems
fair to attribute the occurrence to these agencies known to be present,
and known to be favourable to the production of sickness, and not to
atmospheric contagion, as is almost universally done.
The case of disease appearing in a house previously healthy, after
receiving one just recovered of disease, which it is by the way
consonant with our experience to say, is much more rare than the other,
or that of persons actually ill,—is occasionally noticed, and the
explanation, perhaps, is, that the clothes may retain impurities
acquired during the course of disease, and may on this occasion shew
their activity.