APPLICATION OF THE ARGUMENT. 
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no doubt, the leading character of the organ, there is to be 
seen, in everything belonging to it and about it, an ex¬ 
traordinary degree of care, and anxiety for its preservation, 
due, if we may so speak, to its value and its tenderness. It 
is lodged in a strong, deep, bony socket, composed by the 
junction of seven different bones,* hollowed out at their 
edges . In some few species, as that of the coatimondi,| 
the orbit is not bony throughout; but whenever this is the 
case, the upper, which is the deficient part, is supplied by 
a cartilaginous ligament; a substitution which shows the 
same care. Within this socket it is embedded in fat, of 
all animal substances the best adapted both to its repose 
and motion. It is sheltered by the eyebrows; an arch of 
hair, which, like a thatched penthouse, prevents the sweat 
and moisture of the forehead from running down into it. 
But it is still better protected by its lid. Of the super¬ 
ficial parts of the animal frame, I know none which, in 
its office and structure, is more deserving of attention than 
the eyelid. It defends the eye; it wipes it; it closes it in 
sleep. J Are there, in any work of art whatever, purposes 
more evident than those which this organ fulfils? or an 
apparatus for executing those purposes more intelligible, 
more appropriate, or more mechanical ? If it be overlooked 
by the observer of nature, it can only be because it is ob¬ 
vious and familiar. This is a tendency to be guarded 
against. We pass by the plainest instances, whilst we are 
exploring those which are rare and curious; by which con¬ 
duct of the understanding, w T e sometimes neglect 'the 
strongest observations, being taken up with others, which, 
though more recondite and scientific, are, as solid argu¬ 
ments, entitled to much less consideration. 
In order to keep the eye moist and clean, (which qualities 
are necessary to its brightness and its use,) a wash is con¬ 
stantly supplied by a secretion for the purpose; and the 
superfluous brine is conveyed to the nose through a perfora¬ 
tion in the bone as large as a goose-quill. [Plate IV. fig. 1.] 
When once the fluid has entered the nose, it spreads itself 
upon the inside of the nostril, and is evaporated by the cur¬ 
rent of warm air, which, in the course of respiration, is con- 
* Heister, sect. 89. t Mem. of the R. Ac. Paris, p. 117. 
t The muscles which accomplish these actions are seen in Tab. XIV. 
Fig. 1, 2. The eyelids also moderate the force of a too brilliant light, 
and exclude, by a partial closure, that excess of it which would offend 
the eye. The eyelashes have a similar office, that of regulating the 
quantity of light: and it is believed, that they protect the eye from the 
small particles of dust that float in the air.— Paxton. 
