200 PRINCIPLES AND CONCLUSIONS. 



after which a single bee appeared, soon followed by two others. A half hour 

 later the honey flowers were actively sought, while those without honey 

 were completely neglected. When the yellow flowers were more widely 

 separated and the blue ones so interspersed that one with honey occupied 

 the former position of a similar yellow one, the blue imitations were neither 

 inspected nor visited, though the yellow were busily probed. Placing the 

 two kinds of yellow artefacts in pairs caused those without honey to be 

 often inspected, but the bees quickly learned the position of the honey ones 

 and paid no further attention to the others. Further experiments likewise 

 showed that when the bees did not at first know all the honey artefacts, 

 it was necessary for them to make orienting flights over the two kinds. 

 However, the flights of inspection over the flowers without honey gradually 

 diminished to the point of disappearance. With respect to memory, the 

 second series of experiments indicated that colored objects do not attract 

 bees that are busily at work if they have had no previous experience with 

 imitations. However, when they have repeatedly found honey in an arte- 

 fact of a certain color in one spot, the color continues to exert attraction 

 even when honey is absent, and small displacements of position are imma- 

 terial. It was also demonstrated that bees habituated to gather from honey 

 artefacts at a certain time, namely, 11 to 1 o'clock, did not react to them 

 at a different time, showing that they take note of time as well as of color 

 and place. Further experiments showed that the bees were able to make 

 use of two colors in adjusting themselves to new conditions and that they 

 utilize their sense of color in different and unexpected relations. In short, 

 they are not reflex machines, but their behavior has the stamp of purposeful, 

 intentional acts. 



Frisch's researches. — Sense of color and form in the honey-bee. — 



Frisch has discussed the color and form sense of the honey-bee in a mono- 

 graph of fundamental importance (1914), as well as in shorter articles 

 (1913, 1919). At the present time it is possible only to indicate the scope 

 of his treatment and the general method, and to give his conclusions. The 

 original itself must be studied by all those who wish to carry on accurate 

 work under controlled conditions. The treatise is divided into the follow- 

 ing main sections: (1) demonstration of a color sense; (2) nature of the 

 color sense; (3) the color sense of the honey-bee and flower colors; (4) sense 

 of form and its significance in flower visits ; (5) unsuccessful training experi- 

 ments with unnatural forms; (6) biological notes; (7) practical significance 

 of painting hives in color. The method of experiment consisted essentially 

 in training bees to come to a watch-glass of honey placed on a particular 

 color and following their behavior when such colored squares were variously 

 arranged among gray ones, ranging through all possible shades from white 

 to black and likewise provided with glasses of honey. After two days 

 training with two papers of dull yellow disposed among 30 gray ones, two 

 new yellow papers and watch-glasses, unused and hence free from the odor 

 of bees, were placed in a different position from the first two, which were 

 removed and gray ones substituted. All the watch-glasses were then filled 

 with sugar solution, thus making the conditions on all the papers identical, 

 except for color and brightness. Thus, if the bees were entirely color 

 blind they would see yellow only as a certain degree of brightness without 



