212 SIR JOHN LUBBOCK ON THE SENSE OP COLOB 



yellow and green. Whetlier it actually appears to them as it 

 does to us is of course another and a more difficult question — 

 one, moreover, not yet solved even for the higher animals. Nor 

 would I necessarily claim for them any aesthetic sense of beauty ; 

 hut it must he rememhered that they feed on minute algse and 

 other minute vegetables, the prevalent colors of which are yellow, 

 yellowish green, and green. There is therefore nothing impro- 

 bable, a priori, but rather the reverse, in their preference for these 

 colors. 



It will be observed that though in these vessels the Daphnias made 

 their preference unmistakable, there were always a certain number 

 in the least popnlar part. This is natural, because as the position 

 of the light half was reversed every observation, the Daphnias had 

 to swim across the vessel, and some naturally did not fiud their way 

 to the favourite part. Then, again, in any considerable numbers of 

 Daphnias some are changing, or have recently changed, their skin, 

 and are therefore more or less inactive. Moreover, in pure water 

 the desire for food must often overpower any preference for one 

 color over another. To such causes as these we must, I think, 

 attribute the presence of so many Daphnias in the first vessel at 

 the opaque end, and in the second in the uncovered part. 



Still, it was of course not impossible that the presence, for in- 

 stance, of a certain number under the red and blue was due to a 

 difference of taste, that though the majority preferred yellow, 

 there might be some preferring blue or red. To test this I tried 

 the following experiment. I placed, as before, 50 Daphnias in 

 three of the vessels, covering one half of one with the yellow, of 

 a second with blue, and the third with red. I then from time to 

 time, at intervals of not less than half an houi", removed those 

 which were in the uncovered part and replaced them with an 

 equal number of fresh ones. If, then, some Daphnias preferred 

 red or blue, I ought thus to eliminate the others, and gradually to 

 get together 50 agreeing in this taste. This, however, was not 

 the case. In the first experiment, an hour after the Daphnias 

 were placed in the vessels there were, out of 50, 41 under the 

 yellow, 16 under the red, and 15 u-nder the blue, the remaining 9, 

 34, and 35 respectively being in the uncovered portions. These, 

 then, I removed and replaced by others. After doing this five 

 times, and thus adding 80 in the yellow division, 187 in the red, 

 and 209 in the blue, the numbers were 37 under the yellow, 15 

 under the red, and 6 under the blue. 



