During her delirium the idea of Miss Roseberry's identity ferments in her brain, and assumes its present perverted form.
In that form it still remains.

As a necessary consequence, she persists in reversing the two identities.

She says she is Miss Roseberry, and declares Miss Roseberry to be Mercy Merrick.

There is the doctor 's explanation.

What do you think of it ?" "Very ingenious, I dare say.