152 RELATION BETWEEN ANTS. 
rupted. I put them to a more difficuk 
trial, by digging around their nest a ditch 
several inches in depth. They appeared 
at first to hesitate as to their movement, 
but they did not forget the direction of 
their ant-hill, knowing the way of return- 
ing to it, although the road in this part 
was completely destroyed. When they 
had traversed this furrow, they often re- 
turned behind, exploring the ground, as 
if to observe their route for the purpose 
of again remembering it. 
Why exclude sight, touch, and me- 
mory, from the part they take in regulat- 
ing the conduct of ants? Objects, 
which by us would be passed un- 
noticed on account of their diminutive- 
ness, may be very remarkable with re- 
spect tothem. We may be convinced by 
what follows, of the fidelity of their me- 
mory,’ and of the subtilty of their 
senses. 
If ants had nothing to direct them in 
their journeys but the odour they leave 
after them, how could they possibly as- 
