204 PHYSICAL CAUSES OF 



fear and uncalled for ferocity ; for in the majority of cases 

 for instance, my own, when I have been assailed in spring by 

 fresh or sea-water birds on unwittingly nearing their nests or 

 themselves the supposed intruder or threatener of danger 

 did not dream of the existence of a nest till his attention 

 was thus called to it by the mistaken behaviour of the ruffled 

 and angry mother, whose own best policy would obviously 

 have been to have maintained a discreet silence in hiding 

 beside her young. 



The courage of various birds is developed or stimulated 

 to fury during nidiftcation, or boldness then arises in animals 

 that are at other times timid, such as the tern (White). 

 Similar mental phenomena are exhibited by certain animals 

 during all the stages of incubation and care of the young. 

 The furiosity of the hen during incubation is well known 

 (White). When she becomes a mother she loses her usual 

 placidity ; and so intense is her excitement sometimes that 

 she seems as if ' possessed,' and is popularly so described 

 her mental condition for the moment amounting apparently 

 to an ephemeral mania. 



Just as dentition in the young animal frequently produces 

 the physical state known as ' fever,' so it is also apt to give 

 rise to corresponding mental excitement. In the old, on the 

 other hand, toothache and decayed (carious) teeth are probably 

 no infrequent cause of mental, as well as of bodily, disturb- 

 ance (Crisp). 



The elephant occasionally becomes ' mad with toothache,' 

 and is shot by man while in this state, in consequence of its 

 dangerousness to human life. Thus an Indian official, who 

 reported to his Government the death of such an animal in 

 the Mlghery (^Madras) district, in 1875, remarked : ' His 

 tusk was much diseased, and he must have suffered much 

 from toothache. The portion of tusk imbedded in the flesh 

 was much diseased, and had a knob on it as big as one's fist;' 

 in other words, it was possibly the seat of an exostosis or 

 other morbid growth. 



The effects of moulting are most familiar in the change of 

 the singing ability of certain birds. A caged siskin, belong- 

 ing to &n old friend, droops equally in body and spirit. 



