Except that Lily did figure out what the substitution would do. She immediately figured out that it would make the subject sick and might be deadly, and she eventually figured out that it would make the change permanent (or whatever good thing it did) and would probably not be quite deadly.
Except that Lily did figure out what the substitution would do. She immediately figured out that it would make the subject sick and might be deadly, and she eventually figured out that it would make the change permanent (or whatever good thing it did) and would probably not be quite deadly.