He discusses how his small stature in football made it impossible to realize his dreams of athletic glory. He also notes how his poor health and his lack of military service galled him because he never attained heroic stature in the eyes of the world. This sense of inadequacy permeates his life, and even after coming to terms with the limits of his body, Fitzgerald instead decided to embark upon a 'serious' literary career to prove his worth to the world.
Fitzgerald clearly continued to have a sense of doubt and foreboding about his fragile mental state. However, he attempted to quiet such doubts by repeatedly telling himself that: "Up to forty-nine it'll be all right." Even in this sense of morbidity about his future, there is a great deal of humor in specificity of expected date of the 'crack-up,' once again showing Fitzgerald's use of distance and sense of irony, even when discussing a very personal topic.
However, Fitzgerald experienced a premature 'crack-up' that occurred before the expected 'due date' of forty-nine. In discussing the actual onset of the mental breakdown, Fitzgerald is very vague. There is no discussion of a specific diagnosis. He even begins by using an example of another writer before discussing his own problem, as if trying to keep the crack-up at arm's length throughout the essay for as long as possible. He speaks of another unpleasant tragedy that occurred in his life: "not long before, I had sat in the office of a great doctor and listened to a grave sentence" -- again vague about the nature of what the grave sentence was, or who it was about.
Quickly, once again Fitzgerald uses humor in talking about the initial symptoms of cracking...
Finally, Fitzgerald takes a more serious tone as he talks about his withdrawal from humanity, and his hatred of almost all classes of the human race and utter bitterness about the world.
The crack-up is not a negative development in Fitzgerald's life, though. It brings him to a revelation about himself as a writer. He parallels it with being sick as a student at Princeton and losing everything because of his bout with tuberculosis, which taught him compassion. The crack-up brings about a new seriousness and self-doubt: "That my political conscience had scarcely existed for ten years save as an element of irony in my stuff. When I became again concerned with the system I should function under, it was a man much younger than myself who brought it to me, with a mixture of passion and fresh air."
Although it could be interpreted as a 'bad thing,' Fitzgerald says that: "I have now at last become a writer only." He will cease trying to be who he is not and abandon putting on a false sense of social consciousness and looks for truth in writing. He will be his true self -- warts and all "I do not any longer like the postman, nor the grocer, nor the editor, nor the cousin's husband, and he in turn will come to dislike me, so that life will never be very pleasant again, and the sign Cave Canem is hung permanently just above my door. I will try to be a correct animal though, and if you throw me a bone with enough meat on it I may even lick your hand."
