102 
ANIMAL INTELLIGENCE. 
until by chance I laid them bare. In one case I knew that the 
destruction of the wall had only taken place ten days before, so 
that the seeds had sprouted in the interval. 
My experiments also tend to confirm this, and to favour the 
belief that the non-germination of the seeds is due to some 
direct influence voluntarily exercised by the ants, and not 
merely to the conditions found in the nest, or to acid vapours 
which in certain cases are given off by the ants themselves. 
These experiments consisted in confining a large 
number of harvesting ants with their queen and larvae in 
a glass test-tube partly filled with damp soil and various 
seeds, the whole being closed with a cork in the mouth 
of the test-tube. Under these circumstances the seeds 
all sprouted, showing that mere confinement in an atmo- 
sphere of exhalations from the ants did not prevent germi- 
nation. Another series of experiments, undertaken at the 
suggestion of Mr. Darwin, on the effects of an atmosphere 
of formic acid, showed that although this vapour was very 
injurious to the seeds, it did not prevent their incipient 
germination. Therefore it yet remains to be ascertained 
why the seeds do not germinate in the granaries of the 
ants. 
But in whatever way the ants manage to prevent ger- 
mination, it is certain that they are aware of the 
importance in this connection of keeping the seeds as 
dry as possible ; for Moggridge repeatedly observed that 
when the seeds which had been stored proved over-moist, 
the ants again took them out and spread them in the sun 
to dry, to be again brought into the nest after a sufficient 
exposure. 
Lastly, he also repeatedly observed the most surprising 
and interesting fact that when, as we have seen was occa- 
sionally the case, the seeds did begin to germinate in the 
nests, the ants knew the most effective method of pre- 
venting the germination from proceeding ; for he found 
that in these cases the auts gnawed off the tips of the 
radicles. This fact deserves to be considered as one of 
the most remarkable among the many remarkable facts of 
ant-p sy cb ology . 
Passing on now to the harvest ' 1 g or agricultural ants 
