ACQUIRED SPECIFIC REACTIONS TO COLOR 173 



manner, which as a general mode of explanation of animal 

 behavior is entirely acceptable to the writer, the experimental 

 work upon which Minkiewicz bases his conclusions has never, 

 to the knowledge of the present writer, been satisfactorily 

 presented in any scientific journal. Without exception, Min- 

 kiewicz 's experiments have been stated in a general form so 

 involved in theoretical considerations that the facts them- 

 selves ascertained by experiment have never received proper 

 attention. Until Minkiewicz publishes the actual results of his 

 experiments and not the inferences which he wishes to draw 

 from them, his scientific colleagues will be justified in accepting 

 the alleged results with reservation. 



A second conclusion which can be drawn from our results is 

 that the size of the paper placed in the aquarium has a distinct 

 effect upon the use of the paper for decoration. With bits of 

 paper 5x5 mm. no decoration at all occurred. With the larger 

 pieces decoration resulted in both cases. In view of the results 

 obtained from the blinded crabs it seems likely that the stimulus 

 to the decorating instinct is tactile. Those pieces of paper suffi- 

 ciently large to catch upon the chelae of the crab excite the 

 decorating response. Those pieces, like our 5x5 mm. pieces, 

 which are so small and tenuous as to give no adequate stimulus 

 to the claws of the crab, are passed over unnoticed. 



4. The effect of blinding upon the decorating instinct. — Early in 

 the experiments, the attempt was made to determine by means 

 of an experimentum cruris, the role played by the eyes in the 

 decorating reactions. On the assumption that the reactions 

 were responses to visual stimuli, for on no other assumption 

 could the supposed harmony between the color of the decora- 

 tion and the color of the environment be explained, the elimi- 

 nation of the eyes would abolish the response, unless some 

 other stimulus than visual, could set off the instinct. If some 

 other than a visual stimulus could initiate the response, the 

 resulting decoration ought to bear no relation to the color of 

 the environment, unless the crab possesses color-sensing organs 

 other than the eyes. The result of the next section on the 

 reactions of blinded crabs to light, may be anticipated to the 

 extent of stating that no evidence exists to show that blinded 

 crabs react to light. The eyes therefore are the exclusive light 

 receiving organs. The results with the blinded crabs* show that 



