116 SPECIAL EXPRESSIONS: Chap. V. 



lead me to this inference; but I cannot discover that it 

 is a conclusion admitted by physiologists. Sir J. Paget, 

 however, informs me that when muscles are suddenly 

 contracted with the greatest force, without any prepara- 

 tion, they are liable to be ruptured, as when a man slips 

 unexpectedly; but that this rarely occurs when an 

 action, however violent, is deliberately performed. 



With respect to the upright position of the tail, it 

 seems to depend (but whether this is really the case I 

 know not) on the elevator muscles being more powerful 

 than the depressors, so that when all the muscles of the 

 hinder part of the body are in a state of tension, the tail 

 is raised. A dog in cheerful spirits, and trotting before 

 his master with high, elastic steps, generally carries his 

 tail aloft, though it is not held nearly so stiffly as when 

 he is angered. A horse when first turned out into an 

 open field, may be seen to trot with long elastic strides, 

 the head and tail being held high aloft. Even cows when 

 they frisk about from pleasure, throw up their tails 

 in a ridiculous fashion. So it is with various animals 

 in the Zoological Gardens. The position of the tail, 

 however, in certain cases, is determined by special 

 circumstances; thus as soon as a horse breaks into a 

 gallop, at full speed, he always lowers his tail, so 

 that as little resistance as possible may be offered to the 

 air. 



When a dog is on the point of springing on his an- 

 tagonist, he utters a savage growl; the ears are pressed 

 closely backwards, and the upper lip (fig. 14) is retracted 

 out of the way of his teeth, especially of his canines. 

 These movements may be observed with dogs and pup- 

 pies in their play. But if a dog gets really savage in his 

 play, his expression immediately changes. This, how- 

 ever, is simply due to the lips and ears being drawn back 

 with much greater energy. If a dog only snarls at an- 



