NOVEMBER 269 



a day old, with eyes not yet open. ... It was placed in 

 a small chip box lined with cotton- wool, and kept in a 

 corner of the incubator drawer. So soon as it had 

 taken a morsel or two of food at intervals of about 

 thirty to forty minutes, it would energetically thrust 

 its hind-quarters over the edge of the box and void its 

 excrement. Jays and other young nestlings also show 

 this instinctive procedure. It would be grotesque to 

 credit a blind nestling with conscious and deliberate 

 hygienic precaution. We ride airily out of the difficulty 

 by pronouncing it to be a ' provision of Nature ' that 

 young birds should act in this way for the safety of 

 their own health. I have, indeed, heard this behaviour 

 on the part of young herons described as a deliberately 

 defensive measure. If one climbs a tree in a heronry 

 and approaches a nest containing young birds, they 

 poke their posteriors over the side and discharge a 

 copious and malodorous volley upon the intruder. 

 Such action has all the appearance of design ; but it is 

 almost certainly no more than the natural automatic 

 action of young herons undergoing visceral disturbance 

 through fear or excitement. 



That is an example of very simple functional activity 

 unconsciously performed ; but it can hardly be doubted 

 that some of the most complex and delicate actions 

 of animals very far down in the animated scale are 

 unconsciously performed ; or at least undertaken under 

 a mandate with which they automatically comply. 

 The silkworm once only, and at an immature stage 

 of existence, spins an elaborate cocoon which no 

 amount of practice could improve. The evidence of 



