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HIGHLAND AND AGRICULTURAL SOCIETY. 
time, as always to induce the same epizootic disease. What, in fact, is the 
exciting cause of influenza ? We are ready with the everlasting answer — “ Oh, it 
is atmospheric influence,” — an answer convenient enough to conceal our igno- 
rance, for what that influence is, no one has yet shown. It has been supposed to 
consist in a substance called ozone ; but ozone has met with an able defender in 
my friend, Dr. George Wilson. I believe he has vindicated ozone most com- 
pletely, by showing its beneficial, rather than hurtful, effect on air and life. 
Other gases have been accused, and seleniureted hydrogen among the rest, 
because, along with sulphur, it is evolved during earthquakes and volcanic 
eruptions. These most awful of natural phenomena have been known to precede 
and accompany catarrhal fevers among men and animals, as, for example, Etna 
in 1556, 1675, 1762; Vesuvius in 1737 ; Lipari, 1775; Hecla in 1731. {Ann. 
Inf., p. 381.) Hecker records that along with the plague in Cyprus in 1348 an 
earthquake occurred, and “ a pestiferous wind spread so poisonous an odour, that 
many, being overpowered by it, fell down and expired in dreadful agonies. 
(Hecker’s Epidemics of Middle Ages, Sydenham Society’s edition.) The plague in 
1347 and several following years is said (by Hecker) to have destroyed 25,000,000 
people in Europe. In regard to this, one writer (Copland’s Med. Diet., p. 768,) 
records that it occurred “ independent of irregularity of season.” “ Yet Germau 
accounts say expressly that a thick stinking fog advanced from the east, and 
spread itself over Italy.” (Hecker’s Epid., p. 14.) One thing is certain that * 
accompanying epidemics and plagues destructive epizootics often appeared among 
the lower animals. This fact has been recorded by the earliest poets and by all 
medical historians. Sometimes an apparent glimpse at the causes is thought to 
be seen, but very frequently no cause is traceable. Again, great want of uni- 
formity exists between effects and alleged causes, and epizootics very often occur 
without any cause at all being observed. Many have speculated on this part of 
the subject so much more ingeniously and learnedly than I can do, that I gladly 
leave the matter in their hands. Weather cannot always, at least, be the exciting 
cause, as the disease both in man and beast prevails in all seasons. For instance, 
in regard to epidemic influenza, “ in the year 1836 we find the disorder at the 
same time at Cape Town and London, the season being mid-summer in the one 
place and mid-winter in the other.” {Ann. Inf, p. 382.) “ The influenza of 
1782 prevailed in Russia in the months of December, January, and February, 
and in Italy and Spain during the months of July, August, and September; 
consequently its cause must have been capable of resisting almost the two ex- 
tremes of European hot and cold, — a degree of permanence difficult to' be 
conceived, if we suppose that cause to have existed in the air.” {Ibid., p. 145.) 
Does influenza spread by contagion ? Many veterinarians are of opinion that it 
does. I have never seen good grounds for thinking so myself. Still, in not 
admitting its contagious properties, I am very far from wishing to assert that 
those who differ from me are wrong, and I am well aware that the contagiousness 
of influenza is believed in by practitioners of great judgment, acute observation, 
and ripe experience. I think, however, even these must admit that the disease 
extends between places both near and far, and passes through stables with such 
irregular steps as a supposition of its contagious nature will not explain. No- 
thing, says Dr. T. Thompson {Ann. Inf, op. cit. p. 374,) can more forcibly prove 
the definite character of the influence (causing the disease) than the similarity of 
the symptoms during several centuries, and under such different degrees of 
civilisation. Dr. Holland suggests the probability of its dependence on minute 
or microscopic insects, developed under peculiar states of atmosphere. Mr. 
Grove (see Epidemics Examined) conceives, and on apparently good grounds, 
that the proximate cause of epidemics, and influenza among the rest, depends on 
some organic irritant or principle conveyed by the air. But, amid all suggestions, 
however ingenious, and after considering all theories, however ably supported, 
we are yet uncertain. Being uncertain, then, as to this proximate or exciting 
cause, let us wisely resolve to search for it still, rather than quench the spirit of 
true philosophical inquiry, by binding ourselves to the support of what are only 
theories, and speculating where we ought to investigate. 
Treatment. — In numerous mild cases, occurring where predisposing causes 
are not very influential, a simple attention to what may be called good nursing, 
