THE LIVING STRUCTURES 137 



is not characteristically marked for deceiving his enemy. 

 Many butterflies are veined and marked like leaves and 

 flowers with such splendid accuracy that when they are 

 hidden in the petals of the flowers or hovering on the 

 foliage they are not to be distinguished. Likewise the 

 walking stick insect when it crouches among the green 

 leaves cannot be differentiated from the twigs. Bird 

 hunters are aware that it is difficult to discover grouse 

 and partridges because of their bark-like coloring. 



Nature is so cautious in trying to protect many of her 

 children against their enemies that she often changes 

 their colors with the seasons. Most of the arctic animals 

 change from brown to white as the winter approaches. 

 This is no less true of many kinds of fish. Some have the 

 facilities for harmonizing colors with the particular char- 

 acter of bottom upon which they happen to be resting at 

 the moment. 



The lesson of nature has not been lost upon man. From 

 time immemorial bird hunters have clad themselves in 

 green, that the animals would not distinguish them from 

 the foliage and the surroundings. The American soldiers 

 were the first to adopt the khaki uniform, because it is 

 the color of the earth. European armies have now acted 

 on our suggestion, although it has taken a long time to 

 teach the French soldiers that the bright red on their 

 uniforms is a menace, not an aid. 



Just at present news dispatches tell of the increased 

 number of changes in the army uniforms in an effort to 

 make the soldier invisible or as nearly so as the ingenu- 

 ity of man can make them. Russian artillerymen and 

 scouts have been clad in long white cloaks and caps while 

 fighting in the snow fields of the Carpathians. 



It is said that the adoption of nature's methods of pro- 

 tecting animals has been so successful that it is impos- 



