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ON INSTINCT IN MAN AND ANIMALS. 205 
be so self-evident that they may be taken for granted. 
No one has ever yet obtained the eggs of some bird 
which builds an elaborate nest, hatched these eggs by 
steam or under a quite distinct parent, placed them 
afterwards in an extensive aviary or covered garden, 
where the situation and the materials of a nest simi- 
lar to that of the parent birds may be found, and then 
seen what kind of nest these birds would build. If 
under these rigorous conditions they choose the same 
materials, the same situation, and construct the nest 
in the same way and as perfectly as their parents did, 
instinct would be proved in their case; now it is only 
assumed, and assumed, as I shall show further on, 
without any sufficient reason. So, no one has ever 
carefully taken the pupe of a hive of bees out of the 
comb, removed them from the presence of other bees, 
and loosed them in a large conservatory with plenty 
of flowers and food, and observed what kind of cells 
they would construct. But till this is done, no one 
can say that bees build without instruction, no one 
can say that with every new swarm there are no bees 
older than those of the same year, who may be the 
teachers in forming the new comb. Now, in a scien- 
tific inquiry, a point which can be proved should not 
be assumed, and a totally unknown power should not 
be brought in to explain facts, when known powers 
may be sufficient. For both these reasons I decline to 
accept the theory of instinct in any case where all] 
other possible modes of explanation have not been 
exhausted. 
