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HIGHLAND AND AGRICULTURAL SOCIETY, 
tion of some despised and even invisible classes of the lower 
creation ? Instances of such disturbance in the proportions of 
insect tribes have not been unfrequent, coincidentally with the 
spread of the influenza, and on many other occasions may have 
been easily overlooked. That remarkable coleopterous insect the 
Bostrichus typographus, abounded in 1665, 1757, 1763, and 1783. 
The Arctia Phaeorrhcea committed great ravages in 1731 and 1732. 
In the year 1782 the brown tail moth, that great devastator of our 
hawthorn hedges, occasioned so much alarm in the vicinity of the 
metropolis, that rewards were publicly offered for its destruction ; 
and in October, 1836, vast flights of aphides darkened the air in 
our northern counties. We may just allude, also, to the unusual 
migrations from the continent, in the year 1847, of the cabbage 
butterfly, the bean aphis, and of lady-birds (coccinellae), and also 
of the vanessa cardue flying over a district, in a column from ten to 
fifteen yards wide, for two hours successively.” Besides Dr. T. 
Thompson, many other careful and scientific observers also speak 
favorably of this hypothesis, and connect the prevalence of influenza 
with these organic elements of the air. Such elements may suffer 
“modification more or less extensive in quantity or condition, under 
the influence of raagnetical or other changes, which, by altering the 
relation of the atmosphere to living beings, may thus engender or 
diffuse some peculiar virus adequate to become a cause of disease.” 
— (Annals of Influenza, p. 385.) In objection to this hypothesis it 
may be urged, that it affords only a very partial explanation of the 
disease, and that so long as we are ignorant of the means by which 
those organic grains are themselves produced, we are ignorant of 
the real ultimate cause of influenza. In favour of the hypothesis it 
must, however, be said that it explains more satisfactorily than any 
other yet advanced, the immediate cause of the disease, and the 
peculiarities of its propagation ; and though there is, perhaps, 
scarcely sufficient positive evidence in its favour, there is, at all 
events, no positive evidence against it. It enables us to understand 
why the disease often travels with rapidity from place to place, 
attacking, within so short a time, so many victims ; why it springs 
up at the same time in different localities, sometimes widely sepa- 
rate from each other, as was exemplified in the visitation of 1836, 
which occurred at the same time in London, and at Cape Town ; 
why it is sometimes so irregular and erratic in its progress, leaving 
some individuals and some localities unaffected ; why it appears to 
have many of the characters of contagious disorders, being carried 
about not only by the air, but by clothes ; why it exhibits such 
disregard of external circumstances as climate and general manage- 
ment ; and why it affects about the same time, not only the human 
subject, but horses and others of the lower animals. Further, such 
an hypothesis also affords an explanation of the phenomena of other 
wide-spread diseases which bear some analogy to influenza, as 
cholera, pleuro-pneumonia, and the various eruptive fevers. The 
correctness of this hypothesis is rendered much more probable by 
the fact that many kinds of organic matters, especially when in a 
