ANTS AND SOME OTHER INSECTS. 35 



and most of them to death. In this case a higher decision of in- 

 stinct was victorious over the lower impulse. 



In r/sumJ I would lay stress on the following general conclu- 

 sions : 



1. From the standpoint of natural science we are bound to 

 hold fast to the psychophysiological theory of identity (Monism) in 

 contradistinction to dualism, because it alone is in harmony with 

 the facts and with the law of the conservation of energy. 



Our mind must be studied simultaneously both directly from 

 within and indirectly from without, through biology and the condi- 

 tions of its origin. Hence there is such a thing as comparative 

 psychology of other individuals in addition to that of self, and in 

 like manner we are led to a psychology of animals. Inference from 

 analogy, applied with caution, is not only permissible in this sci- 

 ence, but obligatory. 



2. The senses of insects are our own. Only the auditory sense 

 still remains doubtful, so far as its location and interpretation are 

 concerned. A sixth sense has not yet been shown to exist, and a 

 special sense of direction and orientation is certainly lacking. The 

 vestibular apparatus of vertebrates is merely an organ of equilibra- 

 tion and mediates internal sensations of acceleration, but gives no 

 orientation in space outside of the body. On the other hand the 

 visual and olfactory senses of insects present varieties in the range 

 of their competency and in their specific energies (vision of ultra- 

 violet, functional peculiarities of the facetted eye, topochemical 

 antennal sense and contact-odor). 



3. Reflexes, instincts, and plastic, individually adaptive, cen- 

 tral nervous activities pass over into one another by gradations. 

 Higher complications of these central or psychic functions corre- 

 spond to a more complicated apparatus of superordinated neuron- 

 complexes (cerebrum). 



4. Without becoming antagonistic, the central nervous activ- 

 ity in the different groups and species of animals complicates itself 

 in two directions : (#) through inheritance (natural selection, etc.) 

 of the complex, purposeful automatisms, or instincts ; (l>) through 

 the increasingly manifold possibilities of plastic, individually adap- 



