MENTAL DIFFERENCE AND DISOEDEE. 219 



It is more probably the light than the heat of the sun 

 which, while sought for and enjoyed by the dog when 

 affected by certain diseases (e.g., distemper), is avoided by 

 it in certain others (e.g., rabies). Apparently both solar 

 light and heat perhaps especially the former become in- 

 struments of intolerable pain to the hyper- sensitive rabid 

 dog. By some authors, indeed, but on insufficient grounds, 

 shunning light has been regarded a diagnostic indication of 

 rabies. 



On the other hand, brilliant artificial light exercises a 

 fatal fascination on many animals; so much so that it is 

 made a common basis of modes of capture by man. Brilliant 

 light from candles, gas-jets, or lanterns is a well-known 

 attraction to various insects, birds, and fish, to their own 

 destruction. Many kinds of midges, flies, moths, and but- 

 terflies swarm around, and immolate themselves in, gas, 

 lamp, or candle-lights, as I have myself seen on a large 

 scale in New Zealand. So very familiar is this wholesale self- 

 immolation that these poor animals are popularly regarded 

 as emblems of human folly, of human infatuation, in the 

 non-resistance of dangerous temptation. Butterflies commit 

 this sort of self-destruction in myriads in the street fires of 

 Florence. Lanterns placed under water are used for the 

 capture of certain fish and Crustacea (Houzeau). This, 

 indeed, is the principle of a patent recently granted to the 

 Marquis of Chabannes for catching fish. His apparatus 

 consists essentially of a lighted lamp, sunk in the water, 

 surrounded by mirrors, and connected with a trap of nets 

 into which the fish are allured (Fennell). 



The old practice of c leistering ' or spearing salmon by 

 torch-light, at night, in Scotland, is another ruder modifica- 

 tion of the same principle ; as well as the practice still exist- 

 ing in Fiji and elsewhere of spearing other fish by torch-light 

 (Boddam Whetham). The glare of artificial light or flame 

 is also employed by man in the capture of certain birds. 

 The attraction of lighted wood, or of light or flame of any 

 kind, for the chough leads to accidents from unintentional 

 or mischievous incendiarism (Baird). The woodcock in Loui- 

 siana is killed with poles at night when fascinated or stupified, 



