What are three examples of foreshadowing throughout this book?

“"Such unscientific balderdash,” added the doctor, flushing suddenly purple, “would have estranged Damon and Pythias.”" Chapter 2

Lanyon is talking about the fact that Jekyll is dabbling in things he ought not be dabbling with..... this foreshadows his experiment.

"The last,I think; for, O my poor old Harry Jekyll, if ever I read Satan’s signature upon a face, it is on that of your new friend.”"

This line foreshadows the eventual discover of Jekyll's experiment.

"The figure was stiff; but the signature was good for more than that if it was only genuine."

"I gave in the cheque myself, and said I had every reason to believe it was a forgery. Not a bit of it. The cheque was genuine.”"

The signature on the cheque piques everyone's curiosity and sends up a red flag about the similarities between Jekyll and Hyde's signatures.

“"Yes, sir, he does indeed,” said Poole. “We have all orders to obey him."

All of the servants have orders to obey whatever Hyde asks of them.” This foreshadows the eventual inability for Jekyll to take back his own self.