140 
ANIMAL INTELLIGENCE. 
however, that these and all the above observations, being 
independently made and separately recorded, serve to cor- 
roborate one another so strongly that we can entertain no 
reasonable doubt concerning the wonderful facts which 
they convey. 
I shall now bring these numerous instances to a close 
with a quotation from Mr. Belt, which reveals in the most 
unequivocal manner surprising powers of observation and 
rational action on the part of the leaf-cutting ants of 
South America, wdiose general habits we have already con- 
sidered : — 
A nest was made near one of our tramways, and to get to 
the trees the ants had to cross the rails, over which the waggons 
were continually passing and repassing. Every time they came 
along a number of ants were crushed to death. They perse- 
vered in crossing for some time, but at last set to work and 
tunnelled underneath each rail. One day, when the waggons 
were not running, I stopped up the tunnels with stones * but 
although great numbers carrying leaves were thus cut off from 
the nest, they would not cross the rails, but set to work making 
fresh tunnels underneath them. 
Anatomy and Physiology of Nerve-centres and 
Sense-organs . 
The foregoing facts concerning the intelligence of 
ants fully justifies Mr. Darwin’s observation that 6 the 
brain of an ant is one of the most marvellous atoms of 
matter in the world, perhaps more so than the brain of a 
man.’ It may therefore be interesting in this particular 
case to depart from the lines otherwise laid down through- 
out the present work, and to devote a short section to the 
anatomy and physiology of this nerve-centre with its ap- 
pended organs of sense. 
The brain of an ant, then, is proportionally larger than 
that of any other insect. (See Titus Gfraber, 6 Insects,’ vol. 
i. p. 255.) In structure, also, the brain of an ant is in 
advance of that of other insects, its nearest analogue being 
the brain of a bee. The superiority of development is 
particularly remarkable with reference to the 4 stalked 
bodies ’ of Dujardin ; and these are largest in neuter 
