WHEELER ON ANTS 75 



and sex determination; the wonderful cases of parasitism and symbiosis, and last, 

 but not least, the great importance of these insects in the problems of instinct and 

 intelligence." (pp. 11, 12) 



These sentences are quoted from chapter I, which carries the title " Ants as 

 dominant insects," and serves as an admirable introduction to the more technical 

 materials which follow it. The chapter is throughout quotable and exceptionally 

 interesting to students of animal behavior and psychology. 



There follow chapters on the external and internal structure and the develop- 

 ment of the insects. The descriptions are necessarily brief, but the materials are 

 well chosen and clearly presented. Especially valuable to the naturalist, whether 

 his interests be physiological, psychological, or sociological, is chapter IV, in which 

 a general account of the nervous system is given. 



Of the curious chordotonal organs the author writes," Recent studies have 

 shown that these structures, which are present in a great many insects, even in the 

 larval stages, are typically compact, spindle-shaped bundles of sensillae, each 

 consisting of a chitin-secreting gland and a nerve cell. These cells are arranged 

 in a series at an angle to the integument and are stretched, like a tendon, across 

 a cavity between opposite points in the cuticle, or between a point in the cuticle 

 and some internal organ. The gland cell secretes and retains within its cytoplasm 

 a peculiar cone or rod, known as the scolopal body. The chordotonal organs are 

 supposed to be auditory in function, because they are most elaborately developed 

 in the stridulating Orthoptera (crickets and katydids), and because their structure 

 would seem to be adapted to responding like the chords of a musical instrument 

 to delicate vibrations. In ants the development of these sense-organs is greatly 

 inferior to that of the Orthoptera just mentioned but they are nevertheless very 

 easily seen when one knows exactly where to look for them." (pp. 62, 63) 



In addition to the chordotonal organs, at least six other types of sense-organ 

 are described; the tactile sensillae (organs of touch); the olfactory and gustatory 

 sensillae (organs of smell and taste); the Johnstonian organ (probably an organ 

 of hearing); the campaniform sensillae (whose function is unknown) the lateral 

 eyes and the median eyes or stemmata (organs of vision). 



In a later chapter, XXVII, the functions of the organs of sense are further 

 discussed under the heading," The sensations of ants." At the beginning of this 

 chapter Professor Wheeler makes evident his attitude toward diverse methods of 

 studying animals. He writes, " In endeavoring to gain an insight into the behavior 

 of any animal, two courses are open to us. These may be designated as the intel- 

 lectual and the intuitional, and it depends on the temperament and training of the 

 observer which he will follow, or whether he will be inclined to follow both. The 

 intellectual course is the one usually pursued by the scientist pure and simple, 

 and is especially exalted by those most thoroughly embued with the spirit of our 

 laboratories, where living organisms are best loved when they are dead, or, at any 

 rate, when they can be subjected to the methods of investigation that have yielded 



such valuable results to the development of physics and chemistry The 



intuitionist, in dealing with the behavior of animals, proceeds along the path of 

 aesthetic insight, sympathy and introspective knowledge of our own internal 

 processes. His method is, therefore, essentially psychological and metaphysical. 

 He does not deal with things or quantities, but with the living creative movement 

 as immediately experienced in his own consciousness. He attempts to place him- 

 self en rapport with the organism and to move in the stream of its vital current .... 



