662 POPULAR SCIENCE MONTHLY. 



in many cases colors were useful to the organisms possessing them. 

 Sprengel expressed his belief that the colors of flowers served to- 

 attract insects which aided in the fertilization of the seeds. Other 

 observers showed that dull hues in animals might assist a perse- 

 cuted species to escape from enemies, or a persecuting species to steal 

 upon prev. Such views were at once utilized by the promoters of the 

 celebrated " argument from design," who contended that these crea- 

 tures were so made when created, the useful coloring being con- 

 clusive evidence of a designing intelligence on the part of the Crea- 

 tor. In those days all paths in the fields of science led to the domains 

 .. of theology, where it was unsafe ta 



\ / wander without the guidance of a 



\ / keeper appointed by the church. 



'\ \ ...••■■■ / To this individual puzzling prob- 



'*^> i^i ^f^ l^ms were easy of solution : " God 



v 4. ,-5\v intended it so, and who shall dare 



"'^ ;.) ' to question the actions of Infinity? "' 



V Natural phenomena were given 



y;y ' '%j supernatural explanations which 



,«,^J^k ,,.y ' were accepted in a way that seems- 



ii|,,®r ; * ^ " ' ?^i incredible to us to-day. But gradu- 



' .."-.^ r:yy\ * ]*• \ v^>-^. ■■-■■'> ^lly the law of parsimony in logic 

 ^2f . . : ^f""' ,*. , — the law which in this case di- 



(^^^f ■"■ ^Ir^^ '\..\.'s rected that when a phenomenon can 



u- » '-'J^^Pfi-'^'v"' ^, '''5 be explained in natural terms, we 

 ■<^^..,.,.>.<,,,i^^^'----^-- '^-%.«.„,,,„;^s:.->-' must not appeal to supernatural 



Catocala Morn at Rest. -, ^11 



ones — became accepted, and reasons 

 that had long held good were rejected as worthless. The hold of 

 dogmatism and priestcraft upon science gradually relaxed as the 

 church meddled less in secular matters and religion became an affair 

 of the heart rather than of the intellect. 



It is one of the triumphs of biology — the youngest of sciences — 

 that she has already given an adequate explanation for the existence 

 of most of the phases of animate color. "VVe all now know that the 

 colors of flowers exist, as Sprengel believed, to attract insects, and 

 that insects are attracted to insure cross-fertilization — a fact of which 

 Sprengel was not aware. All tlie world is familiar with accounts of 

 mimicry — " the imposture of ISTature " — as well as of protective and 

 aggressive resemblance. ISTearly every one has seen pictures of the 

 kallima insect, which when in motion is a gaudy butterfly, and at 

 rest becomes a dry and withered leaf; or of the various leaf insects 

 and stick insects of the tropics. Many of us have seen in imagination 

 the puff adder which Professor Drummond did not sit upon in the 

 wilds of Africa, or have watched with Forbes the bird's-dropping 



