the butterfly's seeking its mate, and the prospector's digging 

 for gold are all examples of positive regulation. 



In positive regulation the favorable condition and the 

 adaptive change do not always have the direct relation of 

 cause and effect. They may be as well results of a single 

 cause. This is especially true in the higher forms of be- 

 havior, such as the behavior of a group of sympathetic 

 organisms in a colony or society. For instance, Greek phil- 

 osophy was a cause which has ramified into many results. 

 Largely because of it, and of the development which it 

 caused, the present-day students write their books on science 

 or philosophy, because of it there are laboratories, without 

 which these books would have lacked much material, and 

 printing presses, without which the volumes would never have 

 reached their readers. That same early philosophy is the 

 inheritance of the people and without it the modern book 

 would not be understood. As another example, when the 

 hot weather in spring impels birds to migrate northward it 

 causes also those changes in the country further north which 

 produce food and the proper conditions for raising the young. 

 So we may add: Positive regulation occurs when a process 

 in the manifold which is the cause of some potentially favor- 

 able condition results independently in an adaptive change 

 by which the organism takes advantage of it. 



Both positive and negative regulation may take place as 

 the result of a change merely in the physiological state of 

 the organism and not be due to any variation in the media. 

 Negative regulation is seen under such conditions in the 

 reactions of the over-fed sea anemone away from food, or in 

 behavior of a dog that after a time moves further away 

 from a fire the heat of which had at first attracted him. 

 Positive regulation takes place under like conditions when 

 respiration is increased due to exercise, or when the hungry 

 animal goes out to search for food to which previously it 

 had been indifferent. Judgment and reason in the higher 

 animals furnish the best examples under these conditions for 

 positive regulation. Positive regulation usually results in an 



SEVEN] 



