296 PHILOSOPHY OF ZOOLOGY. 



There is one signal addressed to the eye, apparently em- 

 ployed by many to express certain feelings ; but with whose 

 characters we are imperfectly acquainted. I here allude to 

 luminoumess or phosphorescence. It has been observed of 

 the common glow-worm, that the females, which possess 

 this luminous power in a much greater degree than the 

 males, are destitute of wings ; and, therefore, incapable of 

 flying about in search of a mate ; but that during the sea- 

 son of love, when the light is emitted in greatest brilliancy, 

 she is able to guide her vagrant lover to her presence. By 

 some it has been supposed, that this luminous property is 

 destined to direct the animals possessed of it, with greater 

 certainty to their prey. But it is obvious that it would 

 warn the objects of their pursuit, if animated, of their ap- 

 proach, and facilitate the efforts of their foes to discover 

 their retreat. 



We come now to consider the artificial or acquired signs 

 addressed to the eye. This method of holding intercourse 

 between the individuals of a species, appears to be peculiar 

 to the human race, and to be the instrument by which man 

 can gain possession of the information of past generations, 

 and be able to record the transactions of the present time, 

 for the benefit of future ages. 



If we consider a person in a barbarous state of society, 

 anxious to communicate intelligence to his tribe, respecting 

 an animal which he had observed in the woods, unlike to 

 any in si/e and shape which he had ever seen, we are not 

 aware of any other means which he could employ to accom- 

 plish his object, but to draw its figure upon the sand, or 

 scratch its outline upon the rock. This figure being diffi- 

 cult or tedious to execute, would be abridged in the course 

 of frequent repetition, until it became a symbol merely, in- 

 sU-;ul of a picture, to represent the animal in question. If 

 a particular name was bestowed upon the animal, then the 



