Tender is the Night Book 2, Chapter 2
It was a damp April day in Zurich when Dick went to see Franz Gregorovius, a resident pathologist at Dohmler's clinic. Franz asked Dick about his experiences in the war and if he came to see "that girl", Nicole, who happened to be one of Franz's patients. Dick told Franz that he only saw the girl once, but that she was "the prettiest thing" he ever saw. This girl sent fifty letters to Dick in a span of 8 months. Earlier letters seemed pathological in nature, while more recent letters seemed normal.
The examples of Nicole's letters to Captain Diver showed her fluctuation between insanity and sanity. The first letters were apologetic and nonsensical. She says that Dr. Diver has a "cat's face." In one of her letters she said, "They said that you are a doctor, but so long as you are a cat it is different. My head aches so, so excuse this walking there like a ordinary with a white cat will explain, I think." Book 2, Chapter 2, pg. 122 Nicole kept referring to her sickness, and she repeatedly wrote, "excuse all this". She told him about her experiences with doctors, and how she wanted to leave the institution in Chicago. Some of the letters were desperate, with Nicole pleading for Dr. Diver to help her with her mental problems.
After a month of receiving no letters, Dr. Diver began to receive letters which seemed sane and normal. Her later letters read, "I am slowly coming back to life...I wish someone were in love with me like boys were ages ago before I was sick. I suppose it will be years, though, before I could think of anything like that." Book 2, Chapter 2, pg. 124
If he did not return the letter promptly, however, Nicole became worried. Franz returned and told Dick that he has been waiting to tell him about Nicole.