Aristotle was acquainted with some of the characteristics of the dream-life; for example, he knew that a dream converts the slight sensations perceived in sleep into intense sensations (`one imagines that one is walking through fire, and feels hot, if this or that part of the body becomes only quite slightly warm'), which led him to conclude that dreams might easily betray to the physician the first indications of an incipient physical change which escaped observation during the day. 

1.请问加粗部分如何翻译呢？

2.请分析加粗部分的语法结构，"the first indications of an incipient physical change which escaped observation during the day"在句子中做什么成分呢？

谢谢！