262 MOKBID BODILY CONDITIONS 



Lee asserts that even the embryo in ovo of the octopus 

 becomes flushed with anger afc disturbance, a statement that 

 would scarcely be accepted without ample confirmation from 

 a less known naturalist. And he adds, that the same thing 

 happens to the adult octopus under provocation. 



Colour-changes under excitement from passion or anger, 

 provocation or irritation, for instance or as produced by 

 such various emotions as surprise, fear, or sexual love 

 changes of the hues of the skin or its appendages, are of a 

 varied kind. They have been chiefly studied, and are best 

 known in the chameleon (Darwin). But they have also been 

 observed in the mandrill, the stickleback (Houzeau), the bis- 

 cobra (Darwin), the sporting fish of Japan, and certain 

 other animals. In the sporting fish in captivity in the 

 Jardin d'Acclimatation, Paris, hatred, developed at or by 

 the sight of another individual, causes its naturally grey 

 colour to change to black, while the tail and fin become 

 phosphorescent, and the eyes gleam, furiously. These fish 

 fight for man's sport, ' until one of them returns to its 

 original grey colour, which shows that he has had enough 

 of it.' In many birds the excitement of sexual love causes 

 change of colour in various appendages of the head and 

 throat (Darwin). Other instances of colour-change under 

 emotion, as well as of many other physical modes of ex- 

 pressing mental states, are given or described in the chap- 

 ters on Animal Language. 



In interpreting the causes of such colour-changes, how- 

 ever, we must bear in mind that they are produced also 

 by influences that are not purely mental, or that are not 

 mental at all a circumstance that is well illustrated in the 

 case of the chameleon. c Briicke and others have shown 

 that in the chameleon the changes of tint may be produced 

 by .... the excitements of anger and sexual passion, by 

 illness and by local irritants and nerve- stimulation ' (Francis 

 Darwin) . 



A whole most interesting series of motor disorders, having 

 their seat immediately in the muscular apparatus, but pro- 

 duced through the influence of the nervous system, springs 

 from emotional causes. These disorders range in their 



