INTERCOMMUNICATION 197 
sound appeared to be suggestive of a particular sense-idea in 
the dog. The parent blackbirds, which built near a house in 
Clifton, were wont to give the alarm-note when marauding 
cats appeared in sight. This sound, it would seem, became 
definitely associated, in the experience of a terrier, with the 
animals the presence of which called it forth ; and on hearing 
the alarm note the dog would rush out into the garden, 
apparently, as I am informed by his mistress, in fullest ex- 
pectation of a pleasant worry. It is a not improbable hypothesis, 
therefore, that in the course of evolution the initial value 
of uttered sounds is emotional; but that on this may be 
grafted in further development the indication of particular 
enemies. If, for example, the cry which prompts instant flight 
among the pigs is called forth by a tiger, it is reasonable to 
suppose that this cry would give rise to a representative generic 
image of that animal having its influence on the conscious 
situation. But if the second cry, for defence, was prompted 
sometimes by a leopard and sometimes by some other minor 
foe, then this cry would not give rise to a re-presentative image 
of the same definiteness. Whether animals have the power of 
intentionally differentiating the sounds they make to indicate 
different objects, is extremely doubtful. Can a dog bark in 
different tones to indicate “cat” or “rat,” as the case may 
be? Probably not. It may, however, be asked why, if a 
pig may squeak differently, and thus, perhaps, incidently 
indicate on the one hand “tiger” and on the other hand 
“leopard,” should not a dog bark differently, and thus indicate 
appropriately “ cat” or “rat”? Because it is assumed that the 
two different cries in the pig are the instinctive expression 
of two different emotional states, and Mr. Medlicott could 
distinguish them; whereas, in the case of the dog, we can 
distinguish no difference between his barking in the one 
case and the other, nor do the emotional states appear to be 
differentiated. Of course, there may be differences which we 
have failed to detect. What may be regarded, however, as 
improbable, is the intentional differentiation of sounds by 
barking in different tones with the purpose of indicating “ cat” 
