Early in the chapter, Jem reveals to Scout why he was so shaken by finding his pants crudely mended at the end ch. 6 this:  "'Like somebody was readin' my mind . . . like somebody could tell what I was gonna do.  Can't anybody tell what I'm gonna do lest they know me, can they, Scout'" (58)?  Jem is realizing that while they have been trying to sneak peaks at Boo, he really has been watching them all the time.

This interaction continues in ch. 7 with Jem and Scout finding presents in the tree.  Jem and Scout discuss what to do with their findings.  Jem asserts that they should write a letter and leave it in the tree to thank whoever is leaving the presents.  Then he recalls that a similar plan was how he lost his pants in the previous chapter.  He seems to realize this and stops the idea immediately, which only confuses Scout.  This passage shows us that Jem realizes it is Boo leaving the gifts.  Scout observes, "He had been on the verge of telling me something all evening; his face would brighten and then he would lean toward me, then he would change his mind" (61).  Jem seems to want to tell Scout that it is most likely Boo leaving the presents.

Jem's suspicions are confirmed when Mr. Radley seals the hole with cement.  Jem ends the chapter much like the previous one, alone and in tears.  It is clear that he realizes Mr. Radley is trying to put an end to the innocent communication between the kids and Boo. 

In Chapter 7 of To Kill a Mockingbird Jem starts to realize what kind of a man Boo Radley really is. Previously, he'd subscribed to the dominant notion of Boo as some kind of weird boogie-man, a figure of local legend. But after the incident with his torn pants and finding all those items in the knothole of the tree, he's seen another side of Boo, one that few ever get a chance to see.

Jem's growing realization of Boo's true nature parallels his developing maturity. As Jem's understanding of Boo matures, so too does his personality. Through discovering the very personal items left by Boo in the knothole of a tree, Jem has also discovered that life is a good deal more complicated than he thought—and Scout still thinks. This is an important step on the road to adulthood for Jem.

Jem begins to put all of the events that have occurred together, and he begins to understand more. He had kept the secret of finding his pants folded on the fence to himself. But after Nathan Radley cements the knothole of the tree, Jem is able to understand the situation. He realizes that Boo isn't the enemy; the real enemy is Nathan. All of his old childhood fears are replaced by the reality of what happens. He cries the night Nathan cements the knothole because he understands, not because he's still a child. Jem isn't afraid to ask Nathan why he cemented the knothole, and then he takes the time to put all the pieces together. This is a sign of Jem's passage into a young man and loss of innocent childhood.