18 THE DOG IN HEALTH. 



The development of the puppy and the child are nearly 

 parallel up to a certain stage, when the use of language 

 begins. Previous to that the puppy, in many respects at 

 least, surpasses the infant ; after that the child is of course, 

 on the whole, greatly in advance of the dog. As this 

 idea of human resemblance will be the guiding principle 

 throughout this book, it need not be further dwelt upon 

 just now. 



CLASSIFICATION OF DOGS. 



There can be no doubt that the existing varieties of the 

 dog have been produced by crossing and selection, chiefly 

 aided by the influence of all that enters into the term " en- 

 vironment." Certain breeds have almost or quite disap- 

 peared, and so rapidly are the varieties known in any one 

 country modified that the dog of to-day is in some cases 

 so different from his ancestors of twenty years ago as to 

 be scarcely recognizable as of the same breed, owing to 

 the modifications produced in the way mentioned above. 

 There is in reality no limit to the number of breeds that 

 may be produced. 



The great French naturalist, Cuvier, attempted to give 

 dogs a scientific classification founded on the shape of the 

 head, length of the jaws, etc., while these prominent parts 

 were by him supposed to vary with the peculiar qualities, 

 habits, etc., of the breed. It does not seem possible to 

 classify dogs in this way on a strictly natural basis. As 

 the purpose for which in the main a breed is used by man 

 has much to do with both its form and psychic character- 

 istics, the classification adopted by Stonehenge is at least 

 suggestive. It is as follows : 



