Chap. V. SPECIAL EXPRESSIONS : DOGS. 115 



CHAPTEE V. 



Special Expkessioxs of Animals. 



The Dog, various expressive movements of — Cats — Horses 

 — Ruminants — Monkeys, their expression of joy and 

 affection — Of pain — Anger — Astonishment and Terror. 



The Dog. — I have already described (figs. 5 and 7) 

 the appearance of a dog approaching another dog with 

 hostile intentions, namely, with erected ears, eyes in- 

 tently directed forwards, hair on the neck and back 

 bristling, gait remarkably stiff, with the tail upright 

 and rigid. So familiar is this appearance to us, that 

 an angry man is sometimes said " to have his back up." 

 Of the above points, the stiff gait and upright tail alone 

 require further discussion. Sir C. Bell remarks x that, 

 when a tiger or wolf is struck by its keeper and is sud- 

 denly roused to ferocity, " every muscle is in tension, 

 and the limbs are in an attitude of strained exertion, 

 prepared to spring." This tension of the muscles and 

 consequent stiff gait may be accounted for on the prin- 

 ciple of associated habit, for anger has continually led 

 to fierce struggles, and consequently to all the muscles 

 of the body having been violently exerted. There is also 

 reason to suspect that the muscular system requires some 

 short preparation, or some degree of innervation, before 

 being brought into strong action. My own sensations 



1 ' The Anatomy of Expression,' 1844, p. 190. 



115 



