ORGANIC RESPONSE 257 



permanent alteration of the structure or form of the 

 organism after their cessation. There is another 

 type of response, however, which results in a perma- 

 nent structural change and may therefore be called 

 morphogenetic . 



Non-adaptive Morphogenetic Response. A great 

 many experiments have been tried by different 

 observers to test the effect of various sudden environ- 

 mental changes on developing organisms. Abnor- 

 mal conditions of heat and cold, humidity and 

 dryness, food, etc., have been found to produce re- 

 markable alterations in the color patterns of va- 

 rious butterflies and beetles. Standfuss, Fischer, and 

 others have found that if chrysalids of moths or 

 butterflies are kept in an ice-box prior to emergence, 

 the perfect insects develop many " aberrations," 

 i.e. the color markings of the butterflies are different 

 from the usual type, often to a striking degree. It 

 is very interesting to discover that these artificially 

 produced aberrations are very similar to such as 

 occur in nature and have received names in collec- 

 tions. Particularly is this true of such species as 

 have " winter " and " summer " forms. In most 

 cases, doubtless, the effect of the change in tempera- 

 ture is to directly alter the chemical processes taking 

 place in the color-producing cells of the integument. 

 As a general rule the effect of a slightly increased 

 temperature is to hasten the activity of the color- 

 producing enzymes and hence to increase the inten- 

 sity of the color. With slightly lowered temperature 



