SUDDENLY THE child began to scream, piercing shrieks of terror that died down to shaking sobs, clutching at his mother so that his tiny ringers pinched her skin agonisingly through her flimsy summer dress. Veronica Jones grimaced in the deep green gloom of the reptile house, had to check herself from giving her five-year-old son one of her habitual cuffs across his head. She held him to he