80 



THE SENSE OF HEARING IN ANTS. 



of the spectrum, which no one has ever heard. So that it is 

 not conclusive against the sense of hearing in Ants that they 

 are undisturbed by the violin, the loud shout, and the boats- 

 wain's whistle. For if they cannot hear these sounds they 

 at least may hear others of a different character. 



But neither is it necessary to suppose that they cannot per- 

 ceive sounds that are more than microscopic. It seems to be 

 allowed from the adaptability of any organ or set of organs to 

 the circumstances surrounding it, that the discovery of one-half 

 hinge, so to speak, pre-supposes the existence of something cor- 

 responding to it. For example, the lungs and the wings of the 

 bird have the air to match them, while the gills and the fins of 

 the fish have the water to match them. And in the same way 

 if any animal can produce sound it has organs of hearing to 

 perceive those sounds, so that when we find reptiles in past 

 geological eras with lungs and eyes we infer at once that there 

 was both air and light at the earth's surface at that time ; and 

 by this process of inductive reasoning we conclude that if any 

 animal has ears there must have been sound for it to hear, and 

 if any animal can produce sound, the sound is perceived by some 

 organs without it. 



And from observation we are justified in concluding that the 

 sound which any animal makes is perceived and understood best 

 by its own species. For example, the cow has a distinctive note 

 when calling its calf, and even a caressive murmur when 

 fondling it, which the calf understands quite as well as the bull 

 understands the roar of the other bull's challenge, while these 

 things pass by the grazing horse and sheep as the idle wind, 

 which they regard not. And it is the same with birds, their 

 cries of terror or pleasure are perfectly understood by members 

 of their own species. Even as I have seen a flock of ducks 

 rise at some startled cry of their own species and fly up from a 

 lot of cormorants who stood craning their stupid necks from 

 side to side ignorant of the cause of all this fuss}' flight. 



So with the cat, we are well aware that our nocturnal friends 

 reserve their loudest profanity for each other. 



It is the same with insects. The cicada calls to its fellows. 

 The cricket seeks its mate by its own peculiar chirp. And it 

 seems as if all the faculties of each order, family, genus, and 

 species of animals were designed with reference to those of its 

 own kind almost exclusively. 



I mention this to remove all difficulty from what I am about 

 to say. I have not found any well defined ear in the Ant. But 

 I have discovered an Ant which Prof. M'Coy tells me is un- 



