210 CONFIRMATION OF MY EXPERIMENTS ON ANTS. 



It might be suggested that possibly the ants had 

 been injured or stupefied by the varnishing. M. Forel 

 accordingly, on the following day at 8 a.m., placed over 

 one half of the box a layer of water six centimetres 

 deep, and on the other a piece of red glass, which, 

 while intercepting some of the light, allows almost all 

 the heat to pass through. At 9.25 there were — ■ 



Under the red glass. Under .the layer of water. 



3 varnislied. 11 varnished. 



12 normal. 2 normal. 



Here, it seems that the ants which could see pre- 

 ferred the shade, even though they were rather too 

 warm ; while the hoodwinked ants went under the 

 cool water. 



This indicated that the varnished ants remained 

 sensitive to heat, though not to light. Indeed, Forel 

 states that they were just as lively, just as sensitive to 

 currents of air, as the normal ants.* 



These experiments, then, entirely confirm those I 

 had made. "C'est une confirmation entiere," says 

 Forel, "des resultats de Lubbock j " and he sums up as 

 follows : — The ants " paraissent percevoir I'ultra- violet 

 principalement avec leurs yeux, c'est-a-dire qu'elles le 

 voient, car lorsque leurs yeux sent vernis elles s'y 

 montrent presque indifferentes ; elles ne reagissent 

 alors nettement qu'a une lumiere solaire directe ou 

 moins forte. Les experiences ci-dessus semblent in- 

 diquer que les sensations dermatoptiques sent plus 

 faibles chez les fourmis que chez les animaux etudies 

 par Graber." 



From these and other experiments M. Forel comes 



* Loc. cit., p. 167. t Ibid., p. 174. 



