8 Animal Intelligence 



a thermometer with eyes, but by observing the temperature 

 of his body through other sense-organs so situated that 

 they lead to knowledge of only his own body's tempera- 

 ture. It is important to note that for efficient knowledge 

 of his own body- temperature, John does not use the sense 

 approach peculiar to him, but that available for all ob- 

 servers. He identifies and measures his ' f everishness ' by 

 studying himself as he would study any other animal, by 

 thermometer and eye. 



In the case of the toothache the students proceed as 

 before, except that they use John's gestures, facial ex- 

 pression, cries and verbal reports, as well as his mere 

 bodily structure and condition. They not only observe the 

 cavities in his teeth, the signs of ulcer and the like, but they 

 also ask him, tapping a tooth, "Does it hurt?' "How 

 long has it hurt?' ; "Does it hurt very much?' : and the 

 like. John, if their equal in knowledge of dentistry, would 

 use the same methods, testing himself, asking himself 

 questions and using the replies made by himself to himself 

 in inner speech. But, as with temperature, he would get 

 data, for his identification of the toothache, from a source 

 unavailable for the others, the sense-organs in his teeth. 



It is worth while to consider how they and he would pro- 

 ceed to an exact identification or measure of the intensity 

 of his toothache such as was made of his stature or body- 

 temperature. First, they would need a scale of toothaches 

 of varying intensities. Next, they would need means of 

 comparing the intensity of his toothache with those of 

 this scale to see which it was most like. Given this scale 

 and means of comparison, they would turn John's attention 

 from the original toothache to one of given intensity, and 

 compare the two, both by his facial expression, gestures and 

 the like, and by the verbal reports made. John would 



