56 ANIMAL INTELLIGENCE. 



appeared. Now, three months later, the lower colony has been 

 entirely abandoned. Occasionally, however, especially when 

 fresh and fragrant violets have been placed on the shelf, a few 

 ' prospectors ' descend from the upper nail-hole, rarely, almost 

 never, approaching the vase from which they were first driven 

 away, but seeking to satisfy their desire at the tumbler. To 

 turn back these stragglers and keep them out of sight for a 

 number of days, sometimes for a fortnight, it is sufficient to 

 kill one or two ants on the trail which they follow descending 

 the wall. This I have recently done as high up as T can reach, 

 three or four feet above the mantel. The moment this spot is 

 reached, an ant turns abruptly and makes for home, and in a 

 little while there is not an ant visible on the wall. 



In a subsequent volume of 'Nature' (viii. p. 244), 

 Mr. Darwin publishes another letter which he received from 

 Mr. Hague upon the same subject. It seems that Mr. Mog- 

 gridge suggested to Mr. Darwin that, as he and others had 

 observed ants to be repelled by the mere scent of a finger 

 drawn across their path, the observation of Mr. Hague 

 might really resolve itself into a dislike on the part of the 

 ants to cross a line over which a finger had been drawn, 

 and have nothing to do with intelligent terror inspired by 

 the sight of their slaughtered companions. The following 

 is Mr. Hague's reply to Mr. Darwin's request for further 

 experiments to test this point : 



Acting on Mr. M 's suggestion, I first tried making simple 



finger-marks on their path (the mantel is of marble), and found 

 just the results which he describes in his note as observed by 

 himself at Mentone, that is, no marked symptoms of fear, but a 

 dislike to the spot, and an effort to avoid it by going around it, 

 or by turning back and only crossing it again after an interval 

 of time. I then killed several ants on the path, using a smooth 

 stone or piece of ivory, instead of my finger, to crush them. In 

 this case the ants approaching all turned back as before, and 

 with much greater exhibition of fear than when the simple 

 finger-mark svas made. This I did repeatedly. The final re- 

 sult was the same as obtained last winter. They persisted in 

 coming for a week or two, during which I continued to kill 

 them, and then they disappeared, and we have seen none since. 

 It would appear from this that while the taint of the hand is 

 sufficient to turn them back, the killing of their follows with a 

 stone or other material produces the effect described in my first 



