166 H. C. STEVENS 



trole dans 1 'aquarium blanc-noir-blanc me donna le meme 

 resultat pour les crabes noirs. " 7 The "choice" of costume is 

 thus explained. 8 "L'animal mis dans un milieu colore — vert, 

 par example — en acquerant sous 1 'influence directe du milieu, 

 par resonnance chromo-cinetique, le chromotropisme correspon- 

 dant (synchrome), devient chlorotrope et par consequent negatif 

 vis-a-vis des autres couleurs. S'il trouve des papiers de couleur, 

 il ne peut prendre, c'est-a-dire s'approcher, ni des rouges ni 

 des blancs, etc., ces couleurs faisant dans l'aquarium vert des 

 surfaces negatives (repoussantes) pour l'animal accorde chloro- 

 tropiquement. Or, il se deguisera en vert, qu'll rencontrera en 

 errant sur les surfaces verts. * * * II en est de meme dans 

 un milieu de n'importe quelle couleur excepte le milieu de noir." 

 Minkiewicz here contradicts a statement which is made in the 

 first of the two citations where he says "L 'experience de controle 

 dans l'aquarium blanc-noir-blanc me donna le meme resultat 

 pour les crabes noirs." Briefly put, Minkiewicz's doctrine states 

 that the light receptor system of the crabs, together with their 

 central connections, acquire, by exposure to light of a certain 

 wave length, a specific sympathetic, resonance (synchrone 

 resonnance). By virtue of this specific, sympathetic, resonance, 

 ambulatory movements are initiated which are specific, in the 

 sense that they carry the animal fatally towards the source 

 of light of the same wave length as that to which it has been 

 exposed. Hence the chromo-kine tic-resonance. To obtain 

 experimental evidence upon this subject, a series of obser- 

 vations was made in which certain crabs were exposed to dif- 

 ferent colored lights for a period of time from 24 to 36 hours 

 in length. It was assumed that such a period was sufficient 

 for the animals to acquire the chro mo -kinetic resonance, if 

 such exists. After exposure to the action of the lights, for 

 the times stated, the crabs were placed in the reaction box 

 and their reactions to a series of lights, presented two at a time, 

 one of which was the light to which the animal had been exposed, 

 were determined. The lights used in the reaction box were 

 those used in the experiments already mentioned. The colored 

 light to which the crab had been exposed was presented with 

 each of the other four lights, first on the right, and then on the 



7 Analyse Experiment ale, p. 41. 



8 Ibid., p. 54. 



