4 oS MY LIFE 



waste of wax. The whole conception of a supernatural 

 faculty for the purpose of economizing wax is thus shown to 

 be fallacious. Darwin's explanation entirely obviates this 

 difficulty, since it depends on the bees possessing intelligence 

 enough to reduce all the cellwalls to a nearly uniform thick- 

 ness, being that which is sufficient under all circumstances 

 to support the weight of the whole mass of comb and 

 honey. 



The supposed " homing " instinct of dogs, etc. — In the year 

 1873 one of the many discussions on this subject took place in 

 Nature. I had suggested the immense importance of the sense 

 of smell in enabling dogs to find their way back along a 

 route they had been carried in a basket or covered cart; but, 

 of course, there are cases which this will not explain. I gave a 

 summing up of the whole subject, and added a new and very 

 remarkable case which happened to my friend Dr. Purland, 

 whose amusing letters I have given in chapter xxviii. This 

 case is as follows : — 



" My friend lost a favourite little dog when he was living 

 in Long Acre. Three months afterwards he removed to a 

 house in another street about half a mile distant — a place he 

 had not contemplated going to, or even seen, before the loss 

 of the dog. Two months later (five months after the loss of 

 the dog) a scratching was heard at the front door, and on 

 opening it the dog rushed in, having found out its master in 

 the new house. My friend was so astonished that he went 

 next day to Long Acre to an acquaintance who lived 

 nearly opposite the old house (then empty), and told him his 

 little dog had come back. ' Oh,' said this person, ' I saw the 

 dog myself yesterday. He scratched at your door, barked a 

 good deal, then went to the middle of the street, turned round 

 several times, and started off towards where you now live.' 

 My friend cannot tell how much time elapsed between the 

 dog's leaving the old and arriving at the new house. If every 

 movement of this dog could have been watched from one 

 door to the other, much might have been learnt. Could it 

 have obtained information from other dogs? Could the 



