75 
SENSE OF SMELLING. 
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a peculiar mechanism by which they can, at will, convert the eye 
into a telescope of extraordinary power : and I imagine that it is 
by the sense of sight principally that they distinguish their prey. 
They are said to recognise the peculiar smell of approaching 
death. The crow and the raven will hover over the weakly 
lamb, and sometimes attack him before he is dead. Who has 
not observed, with a thrill of horror, the vultures following the 
ill-fated Mazeppa, in that beautiful engraving depicting his cruel 
punishment ? I do not imagine that the scent is here concerned, 
but they see that their destined prey is w r eak and nearly ex¬ 
hausted, and are hovering round to pounce upon it as soon as, or 
before, life is extinct. 
If the sense of smell be thus acute in all our patients, we ac¬ 
count for it as a provision wisely and kindly made to guide them 
to their proper food, or fit them for our service; but there is an 
important use that we may possibly derive from our knowledge 
of this extreme sensitiveness, namely, to guard a little the mem¬ 
brane of the nose from some of the injuries and dangers to which 
it is exposed. Persons bottling a considerable quantity of spirit 
have become partially intoxicated by the impression of the va¬ 
pour of the liquid on the nerves of the Schneiderian membrane, 
whether the sensitive or the olfactory. One of my men used to 
be regularly purged when he pounded aloes. 
The Membrane of the Nose is a vulnerable Part .—Contagion 
results from certain miasmata or poisonous particles diffused 
through the air. Their impression may be made on the Schnei¬ 
derian membrane and not on the lungs, or, at least, principally 
on that membrane. I consider the membrane of the nose (and 
thus I shall have to describe the larynx to you) as a guard to the 
lungs. Of the more solid particles which enter the nostril, few 
or none are permitted to reach the lungs, and not even the 
larynx. I might appeal to the habitual snuff-taker in proof of 
this. He may load his nostril as he will, but not one atom of the 
deleterious powder reaches the lungs. So the deleterious gases 
are arrested, possibly absorbed, by the mucous membrane on 
which they impinge. 
The Schneiderian membrane, then, is probably a vulnerable 
part. It may be the medium through which much evil is com¬ 
municated, and contagion conveyed. The particles may not be 
sufficiently numerous or powerful to reach or dangerously affect 
the lungs, but they are arrested by the mucous membrane of the 
nose, and absorbed by it, and the constitution becomes thus 
affected. A smaller quantity of poisonous exhalation or gas may 
here make its fatal impression. There appears the greater necessity 
for attention to ventilation, and especially for preserving this 
