30 NATURAL THEOLOaY. 



every thing belonging to it and about it, an extraordinary 

 degree of care, an 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,t the orbit is not bony 

 throughout ; but whenever this is the case, the upper, which 

 is the deficient part, is supplied by a cartilaginous hgament, 

 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 

 Are there in any work of art whatever, purposes more evi- 

 dent than those which this organ fulfils ; or an apparatus 

 for executing those purposes more intelligible, more appro- 

 priate, or more mechanical ? If it be overlooked by the ob- 

 server of nature, it can only be because it is obvious and 

 familiar. This is a tendency to be guarded against. We 

 pass by the plainest instances, while we are exploring those 

 which are rare and curious ; by which conduct of the under- 

 standing we sometimes neglect the strongest observations, 

 being taken up with others which, though more recondite 

 and scientific, are, as solid arguments, entitled to much less 

 consideration. 



In order to keep the eye moist and clean — which quali^ 

 ties are necessary to its brightness and its use — a wash ifc 

 constantly supplied by a secretion for the purpose ; and the 

 superfluous brine is conveyed to the nose through a perfora- 



* Heister, sect. 89. 



t Memoirs of the E^oyal Academy, Paris, p. 117. 



