FIRE AS AN AGENT IN HUMAN CULTUBE 187 



species possess light organs as part of their economy. Hence the 

 lures of hunters and fishers, and the sexual and other Im^es of light- 

 producing animals. It has perhaps been less noticed that the habits 

 of animals are much modified by the artificial lights of man, especially 

 under the relatively great increase of gas and electric illumination. 

 Night-flying insects generally have suffered, because their reaction 

 to light is total. Day-flying insects have taken on an extended term 

 of activity, as may be observed in the change in the habits of the 

 house fly. The tragedies which surround an open arc lamp are fa- 

 miliar to city dwellers, and among the myriads of dead or stunned 

 insects, bats, and toads ply their quest by the aid of artificial light. 

 The lights along trolley lines and country roads also must be respon- 

 sible for great dislocations in the habits of animals. Migratory birds 

 have suffered losses from lighthouses, not being, as commonly said, 

 bewildered by the glare, but more probably yielding to the attrac- 

 tion of light. 



Observations seem to render it possible to classify animals by 

 their reactions to artificial light into animals averse to light, those 

 neutral or favorable to light, and those more or less strongly attracted 

 by light. There would be considerable discussion for and against as 

 to natural reactions to light of the different races of mankind if such 

 a statement were brought forward that tropical man dislikes light. 

 Temperate Zone man is neutral to light, and Frigid Zone man likes 

 light. In reality the preponderant factor here is the preservational 

 instinct by which man adjusts himself to his surroundings. A pro- 

 found need, however, is expressed by the fact that artificial light is 

 one of the more promin.ent inventions which man has brought to his 

 aid and at which he has assiduously worked. The use of artificial 

 light has become a human characteristic. Some observations on the 

 zonal environments connected with the development of artificial illu- 

 mination and its chief features are sketched below. 



In civilization, where social differentiation had developed the 

 active, cultured, enterprising, intellectual, ecclesiastic, and parasitic 

 classes, the need for more light was first felt. The weary masses 

 remained practically in a primitive state with regard to the common 

 uses of fight, and the bulk of humanity still remains so. This vast 

 substratum forms the material upon which the iUumination engineer 

 works, and the economic possibihties here are apparent. 



THE TE0PIC3 



The equality of duration of day and night in the Tropics tends to 

 conservatism in the arts of life. It will be seen that in the Tropics 

 inventions for the production of artificial illuminaton are most 

 primitive. The Tropics are overwhelmingly in the torch and candle 

 stage, and show only a rudimentary beginning of the lamp in some of 

 102837—26 14 



