262 WILD TRAITS IN TAME ANIMALS. 



the nostrils, but from the general surface of 

 the body. The other day while a kitten was 

 purring on my knee I took my phonendoscope 

 (which is a modern form of stethoscope some- 

 what on the microphone principle) and care- 

 fully investigated the origin and character of 

 the sound. I found that the purring was so 

 fully conveyed through the creature's lungs to 

 the chest wall that its ribs vibrated almost like 

 the woodwork of a violin. Heard in this way, 

 the purring of a cat has a most curiously 

 exact resemblance to the sound made by a 

 powerful dynamo, and as I stroked the cat's 

 fur the crackling of electric sparks — also mag- 

 nified by the phonendoscope — added to the 

 deception. Needless to say, I do not advance 

 this as another remarkable case of protective 

 mimicry ! Tempting as such a hypothesis as 

 to the origin of the purr may appear to a 

 baffled evolutionist, it must be admitted that 

 dynamos scarcely played a sufficient part in 

 early mammalian development to have become 

 exemplars for future generations of mimics. 



A cat's scrupulous cleanliness is certainly one 

 of the chief traits which render the animal a wel- 

 come inmate of our houses. The force of the 



