Boris is as adverse to a bath, and as hard to get out of it once in, as any human child; but, since he's a polar bear, the details of his situation are entrancingly different. The faucets on his tub say ""COLD"" and ""COLDER""; Mrs. Bear adds ice cubes and warns that if he doesn't hurry the water will get warm; mow blows in the open window; and Boris' pet is a live penguin. The idea may be slight, but it's unusual and cleverly developed. White's attractive double-spread paintings--with the cool hues of shadows on snow brightened with sunset colors-nicely extend the humor. Just right for a change of pace at picture-book hour or bedtime.