26 A NATURALIST IN HIMALAYA 



of seeds it is, I think, by the sense of smell that it 

 finds its way back again to its track. To test this 

 I placed near the nest away from the track a perpen- 

 dicular stick with a little platform on the summit on 

 which were laid some chopped walnuts. I transferred 

 a few ants to the platform, and after a little time they 

 continued to come backwards and forwards between 

 the platform and the nest, on all occasions making a 

 straight course from the foot of the stick to the 

 opening of the nest. While an ant was selecting a 

 suitable morsel on the platform I moved the stick one 

 inch to the right. The ant descended the stick with 

 its load, but when it reached the ground, instead of 

 making direct for the nest it wandered aimlessly about, 

 carried its load further and further away until finally 

 I lost it in the grass. It could not have been a special 

 sense of direction that guided the ant from the foot of 

 the stick to the nest, for the movement of the stick 

 one inch did not appreciably alter its relationship and 

 direction in respect to the nest, yet the ant was hope- 

 lessly lost. I believe the ant, when away from the 

 common road, on its return journey follows the line of 

 its own scent, and when it deviates from that line it is 

 lost. And if this be true, then the sense of smell must 

 be developed to an inconceivable degree. It is in 

 itself surprising to watch the thousands of ants moving 

 along the common track, each guided by a powerful 

 sense of smell ; but it is far more wonderful to see a 

 single ant, away from the beaten road, scenting back 

 along its own track and unerringly working over the 

 same line that it previously followed, though that line 

 may have been crossed and recrossed in the interval 

 by hundreds of other ants, A harvester must, there- 



