266 DARWINISM STATED BY DARWIN HIMSELF. 



of much disservice, and can not have been at first ac- 

 quired through the will, and then rendered habitual in 

 association with any emotion. I am assured by an emi- 

 nent authority that young children do not tremble, but 

 go into convulsions, under the circumstances which would 

 induce excessive trembling in adults. Trembling is ex- 

 cited in different individuals in very different degrees, 

 and by the most diversified causes — by cold to the surface, 

 before fever-fits, although the temperature of the body is 

 then above the normal standard ; in blood-poisoning, de- 

 lirium tremens, and other diseases ; by general failure of 

 power in old age ; by exhaustion after excessive fatigue ; 

 locally from severe injuries, such as burns ; and, in an 

 especial manner, by the passage of a catheter. Of all 

 emotions, fear notoriously is the most apt to induce 

 trembling ; but so do occasionally great anger and joy. 

 I remember once seeing a boy who had just shot his first 

 snipe on the wing, and his hands trembled to such a de- 

 gree from delight that he could not for some time reload 

 his gun ; and I have heard of an exactly similar case 

 with an Australian savage, to whom a gun had been lent. 

 Fine music, from the vague emotions thus excited, causes 

 a shiver to run down the backs of some persons. 



"When animals suffer from an agony of 

 pain, they generally writhe about with fright- 

 ful contortions ; and those which habitually use their 

 voices utter piercing cries or groans. Almost every mus- 

 cle of the body is brought into strong action. With man 

 the mouth may be closely compressed, or, more com- 

 monly, the lips are retracted, with the teeth clinched or 

 ground together. 



