DIFFERENCE AND DISORDER. 187 



Thus the exciting or immediate cause of insanity in the 

 horse is sometimes simply the sight of the conditions under 

 which it has been overworked or ill-used ; while accessions 

 of fury in the same animal are occasionally determined by 

 mere touch (Pierquin), just as they are in the rabietic dog 

 by sights, sounds, or other sensations. It illustrates the 

 saying, ' What great events from trivial causes spring,' that 

 the rabbit, dog, cat, sow, and other animals require only the 

 slightest disturbance of themselves or their lairs to lead them 

 to devour their own young (White). 



Domestic quarrels, some slight, real or supposed, the 

 presence of some stranger, may develop cannibalism, espe- 

 cially in the mother recently delivered. But in such a case 

 we have, along with a trivial exciting cause, a very powerful 

 predisposing one ; and the converse also frequently happens, 

 that a powerful exciting cause may suffice when the predis- 

 position is small, or appears to be absent. In the puerperal 

 state of the rabbit and other animals, as is shown in the 

 chapters on ' Physical Causes,' there is a morbid receptivity 

 of impressions on the senses a morbid impressionability or 

 sensitiveness just as there is also in rabies. 



The apparent triviality of causation is frequently re- 

 markable in various forms of insanity, in panics or stampedes, 

 in all degrees of fear and of fury. The immediate cause of 

 abjectness of terror in a horse may be merely a piece of 

 white paper rolling or rustling along the road before the 

 wind in the twilight. But the probability is, in such a case, 

 that the animal is highly nervous, sensitive, or impression- 

 able. Soiling of their fur by young guinea pigs, we are told, 

 may lead to dislike to them by their own mother, and the 

 cause of other singular antipathies is even more trivial. The 

 marked liability of captive monkeys to outbursts of passion 

 is connected usually with trivial causation. Thus the couxio 

 (monkey) loses its temper, flies into a rage, at mere wetting 

 of its beard (Cassell). The exciting cause of panic is fre- 

 quently, though not in all cases, most trivial, so much so 

 that it may be difficult or impossible to discover it ; or when 

 discovered, to believe it can have had any influence in the 

 production of results so serious. The same piece of white 



