GENERAL HISTORY 9 



great as it seems, since we know that jackals, wild dogs, and 

 wolf pups reared by bitches readily acquire the habit. On 

 the other hand, domestic dogs allowed to run wild forget how 

 to bark, while there are some which have not yet learned so 

 to express themselves. 



The presence or absence of the habit of barking cannot, 

 then, be regarded as an argument in deciding the question 

 concerning the origin of the dog. This stumbling block 

 consequently disappears, leaving us in the position of agreeing 

 with Darwin, whose final hypothesis was that "it is highly 

 probable that the domestic dogs of the world have descended 

 from two good species of wolf (C. lupus and C. latrans), and 

 from two or three other doubtful species of wolves namely, 

 the European, Indian, and North African forms ; from at 

 least one or two South American canine species ; from several 

 races or species of jackal ; and perhaps from one or more 

 extinct species " ; and that the blood of these, in some 

 cases mingled together, flows in the veins of our domestic 

 breeds. 



