CATS AND DOGS 377 
by different peoples in prehistoric times. Then, by inter- 
breeding and selection there was obtained the great diversity 
in size and form that we see among the 200 breeds of dogs 
we now have. These have usually been developed for special 
purposes. For example, the pointer and the setter are 
favorite bird dogs; the water spaniel, Chesapeake bay, and 
Brown WATER SPANIELS 
Newfoundland dogs excel as water dogs; the terriers have a 
propensity for digging the ground in pursuit of their prey, 
and can be trained to make war upon rats; the collie is the 
celebrated sheep dog of Scotland; bulldogs are very mus- 
cular and strong and are remarkable for their courage and 
ferocity ; while the poodle and the pug are chiefly used for pets. 
