In the scene where Jonathan picks up the scarab, it breaks open and the beetle inside starts to crawl under his skin. We see Brendan Fraser tear Jonathan's shirt and cut the beetle out of him. However, in the very next scene, we see Jonathan walking into the temple, his shirt is intact and there is no blood to be seen.
An explanation for why there is no salt acid booby-trap protecting the gold book like there was protecting the black book. In the missing scene some of Imhotep's priests burst through the floor/ground and attack Jonathan and Rick, who get tossed aside. The priests then open the gold book's hiding place and get burned all up by the salt acid. You can even see when Rick grabs the TNT that there is smoke rising from the hole.