INTEGRATION OF AGGREGATIONS 95 



since the termites were standing on many different dead leaves scat- 

 tered over a considerable radius. Gounelle (1900) had previously 

 described the sound produced by termites by tapping their heads on 

 plants as being Hke the sound produced by a pinch of sand hitting 

 paper, but he did not record synchrony. Emerson (1928) found that, 

 despite the possession of the so-called "auditory organs" on the 

 tibiae, N asutitermes giiayanae did not respond to a wide range of 

 aerial sounds but did react to substratum vibrations. 



Much emphasis has been placed on the role played by the human 

 voice in the integration of human society; some social psychologists 

 prefer to define man as a language animal. In this, man does not 

 appear to be unique except in the degree to which language has been 

 developed in his species. Craig (1908), in discussing voices of pi- 

 geons as a means of social control, finds that in animals with so 

 highly developed instincts as birds there is still much of the social 

 life that cannot be explained on an instinctive basis. The reaction of 

 the individual pigeon must be adjusted to meet the activities of other 

 birds, its parents, its mate, its young, its neighbors, and chance 

 strangers. The adjustment is very delicate and requires that each 

 individual must be susceptible to the influence of others, an adjust- 

 ment which is largely accomplished by vocal means. 



Perhaps more time has been spent on the vocal-auditory method 

 of group integration than is justified by the conditions obtaining 

 at the aggregation level with which this study is immediately con- 

 cerned. Its interest by reason of its importance with the higher ani- 

 mals must be the excuse. 



INTEGRATION BY LOW-FREQUENCY VIBRATIONS 



Much experimentation shows that animals that give little or no 

 indication of perceiving sound vibrations coming through the atmos- 

 phere respond definitely to vibrations of similar or lower frequency 

 coming to them through water or through the substratum. With 

 catfish, Bowen (1930) finds that blinded animals give definite reac- 

 tions to the passing of another fish or of a model with a posterior 

 part vibrating somewhat as does the tail of a fish. Such reactions are 

 dependent on the presence of the sense organs of the skin. When 



