THE SENSATIONS OF AXTS. 5 11 



of the track by the antepenultimate joint, through the air; the odor 

 of the inert young, and probably that of the queen also, by contact, 

 through the two joints above, or proximal to those last mentioned, 

 while the next above these by contact also discerns the specific odor.' 

 This statement not only lacks confirmation by other observers, but seems 

 to be the only one which implies that the olfactory organs of an animal 

 may exhibit regional differentiations. This has not even been claimed 

 for dogs, which, nevertheless, possess extremely delicate powers of 

 odor discrimination and association. This would be no serious objec- 

 tion, however, if we were able to discover the slightest support for 

 Miss Fielde's hypothesis in the structure of the antennae. We do. 

 indeed, find in the funiculi a variety of sensillae, as has been shown in 

 Chapter IV, but none of these is confined to a single joint or to two 

 joints. Miss Fielde, moreover, completely ignores the tactile organs 

 of the antennae and makes this surprising statement : ' During five 

 years of fairly constant study of ants I have seen no evidence that their 

 antennae are the organs of any other sense than the chemical sense." 

 And still she observed that ants that had lived in a Petri dish for over 

 a year felt perfectly at home in any new Petri dish to which they were 

 transferred. For an interpretation of such a case of " recognition " 

 one would certainly turn to a mechanical rather than to a chemical 

 sense. Many of her interpretations of the behavior of ants with muti- 

 lated antennae are open to the obvious objection that she tacitly denies 

 the existence of perception where there is no visible response or where 

 the animal inhibits certain of its activities. If we add to this objection 

 the very limitations of the method, /. c., the necessity of removing all 

 the joints distal to the one whose function is being tested, and the con- 

 sideration that the hypothesis is not needed in explaining the facts, it 

 will be seen that we are not sufficiently justified in regarding the ants' 

 antenna as an organ made up of a series of specialized " noses." 



It is not always easy to distinguish taste from smell in our own 

 sensory experience, and in ants, where even the structure of the sen- 

 sillae in the antennae and mouthparts are very similar, the difficulty is 

 greatly enhanced. That the rows of sensillas on the maxillae and at 

 the base and tip of the tongue are the organs of taste seems to be 

 proved by the observations of Forel (i886-'88, 1900-01 ). He found 

 that " when morphine or strychnine are mixed with honey, the ants fail 

 to detect these substances with their antennae. The odor of the honey 

 attracts them and they begin to eat it. Rut as soon as their mouth- 

 parts come in contact with it they at once turn away. It is easy to 

 observe the preferences of ants for certain viands; they will partake 

 of some and not of others, but they will neglect everything, sometimes 



