"Dear Doctor Isaacson:

"My health," etc., etc.

He opened another:

"200, Park Lane, Jan. ——

"Dear Doctor Isaacson:

"I don't know what is the matter with me, but—" etc., etc.

He took up a third:

"1x, Berkeley Square, Jan. ——

"Dear Doctor Isaacson:

"That strange feeling in my head has returned, and I should like to see you about it," etc., etc.