REVIEWS AND EXCHANGES 
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wrote down the titles of the offices and the names of the Lilteral leaders on pieces 
of paper, and tried all the evening, but in vain, to tit them together. At last 
they gave it up and went to bed. When Mr. Gladstone awoke in the morning 
everything was satisfactorily arranged in his head ; his brain had worked it out 
for him during his sleep. This was not conscious reason, and certainly was not 
instinctive. Dr. Carpenter gave to such action the name of unconscious 
cerebration. 
The nests of birds and cells of bees, the search for food, for warmth, and 
other similar actions necessary to life, may, to some extent, at any rate, be 
plausibly explained away. No one attributes anything approaching reason, or 
even sensation, to plants. 
The social habits of ants, however, afford other arguments which seem con- 
clusive. Take first their relations with other insects. Those between ants and 
aphides, which have been called ant cows, are indeed most remarkable. It 
is not merely that the ants milk them, tend them, defend them from attack, 
sometimes protect them by earthen enclosures from too great summer heat, but 
over and above all this they collect the eggs in autumn, keep them through the 
winter, and plant them out on their proper plant in the spring. .Some of the root 
aphides may always be found in ants’ nests, but I was much puzzled years ago 
by finding in ants’ nests some black eggs, which obviously were not those of ants. 
Eventually I ascertained that they belonged to a species of aphis which lives on 
the leaves and leaf-stalks of plants. 
These eggs are laid early in October on the food-plant of the insect. They 
are of no direct use to the ants, yet they are not left where they are laid, exposed 
to the severity of the weather and to innumerable dangers, but are brought into 
their nests by the ants, and tended by them with the utmost care through the 
long winter months until the following March, when the young ones are brought 
out and again placed on the young shoots of the daisy. This seems to me a 
most remarkable case of prudence. Our ants may not, perhaps, lay up food for 
the winter, but they do more, for they keep during six months the eggs which 
will enable them to procure food during the following summer, a case of prudence 
unexampled in the animal kingdom. 
Dr. Forel refers to the phenomena of memory as very conclusive. That 
insects remember cannot be doubted, for, as he observes : — 
“The slavemaking ants {Po/yer^s) undertake predatory expeditions, led by 
a few who for days and weeks previously have been searching the neighbourhood 
for nests of Formica fusca. The ants often lose their way, remain standing, and 
hunt about for a long time till one or the other finds the topochemical trail, and 
indicates to the others the direction to be followed by rapidly pushing ahead. Then 
the pupre of the Formica fusca nests, which they have found, are brought up from 
the depths of the galleries, appropriated and dragged home, often a distance of 
forty metres or more. If the plundered nests still contain pupte, the robbers 
return on the same or following days, and carry off the remainder ; but if there 
are no pupte left they do not return. How do the Polyergiis know whether 
there are pupre remaining ? It can be demonstrated that smell could not attract 
them from such a distance, and this is even less possible for sight or any other 
sense. Memory alone — r.«., the recollection that many pup.ie still remain behind 
in the plundered nest — can induce them to return. I have carefully followed a 
great number of these predatory expeditions.” 
Again, ants are influenced by circumstances which can only affect mind. 
Dr. Forel says: — 
“ While success visibly heightens both the audacity and tenacity of the ant- 
will, it is possible to observe, after repeated failure or in consequence of the 
sudden and unexpected attacks of powerful enemies, a form of abulic dejection, 
which may lead to a neglect of the most important instincts, to cowardly flight, 
to the devouring or casting away of offspring, to neglect of work and similar con- 
ditions. There is a chronically cumulative discouragement in degenerate ant- 
colonies and an acute discouragement when a combat is lost ; in the latter case 
one may see troops of large, powerful ants fleeing before a single enemy, without 
even attempting to defend themselves, whereas the latter a few moments pre- 
viously would have been killed by a few bites from the fleeing individuals.” 
Mr. Grote, the historian, in his “Fragments on Ethical Subjects,” regard 
