ANTS AND SOME OTHER INSECTS. 39 



tinguish plants, other animals and food, except in so far as the 

 visual and gustatory senses are concerned in these activities. These 

 two senses may be readily eliminated, however, since the latter 

 functions only during feeding and the former can be removed by 

 varnishing the eyes or by other means. Many insects, too, are 

 blind and find their way about exclusively by means of their an- 

 tennae. This is the case, e. g. , with many predatory ants of the 

 genus Eciton. 



But I will here assume these questions to be known and an- 

 swered, nor will I indulge in polemics with Bethe and his asso- 

 ciates concerning the propriety of designating the chemical anten- 

 nal sense as "smell." I have discussed this matter elsewhere. 1 

 What I wish to investigate in this place is the psychological quality 

 of the antennal olfactory sense, how it results in part from observa- 

 tion and in part from the too little heeded correlative laws of the 

 psychological exploitation of each sense in accordance with its 

 structure. I assume as known the doctrines of specific energies 

 and adequate stimuli, together with the more recent investigations 

 on the still undifferentiated senses, like photodermatism and the 

 like, and would refer, moreover, to Helmholtz's Die Thatsachen in 

 der Wahrnehmung, 1879. Hirschwald, Berlin. 



When in our own human subjective psychology, which alone 

 is known to us directly, we investigate the manner in which we in- 

 terpret our sensations, we happen upon a peculiar fact to which 

 especially Herbert Spencer has called attention. We find that so- 

 called perceptions consist, as is well known, of sensations which 

 are bound together sometimes firmly, sometimes more loosely. The 

 more intimately the sensations are bound together to form a whole, 

 the easier it is for us to recall in our memory the whole from a 

 part. Thus, e. g., it is easy for me to form an idea from the thought 

 of the head of an acquaintance as to the remainder of his body. In 

 the same manner the first note of a melody or the first verse of a 

 poem brings back the remainder of either. But the thought of an 



1 " Sensations des Insectes," Rivista di Biologia Generate. Como, 1900-1901. 

 For the remainder see also A. Forel, Mitth. des Munchener entom. Vereins, 1878, 

 and Recueil. Zool. Suisse, 1886-1887. 



