THE CITY OF PETRÓPOLIS, in the mountains above Rio de Janeiro, is a suggestive place. It suggests, first of all, a benevolent nature, not the wild, threatening mass found elsewhere in Brazil, with its disease-bearing insects and its swarms of cannibalistic fish, but a carefully tended tropical nature of the kind found in the better Hawaiian or Balinese resorts. Here, nature means gentle streams lined with colorful, bushy impatiens. It means broad sheltering trees, and cute little monkeys playing in them. In Petrópolis, the weather is cooler, the breezes are softer, than in Rio de Janeiro, the