What are two examples of humor in the anecdote about Stivvings?

The narrator J. tells the story of the boy named Stivvings in four paragraphs appearing in Chapter VI. To J.’s mind, the first remarkable characteristic of Stivvings was the fact that he enjoyed going to school. He liked to study and to learn Greek, French, and German. He wanted to do his best, to earn awards and prizes, and to make his parents proud. Now, in theory, these are the expectations, assumptions, and hopes that teachers have for every student. But J.’s close circle of friends didn’t like school. They felt it was something to rail against. J. says of Stivvings that he was full of “weak-minded ideas. I never knew such a strange creature, yet harmless, mind you, as the babe unborn.”  This statement is humorous and ironic because Stivvings is the model of a normal student. He’s not supposed to be considered “a strange creature.”
The second remarkable characteristic of Stivvings was the fact that he was almost always sick. J. outlines in lengthy detail the kinds of maladies that the boy suffered from during the school year. Now, sickness of any kind is hardly something to make fun of. But J. does this successfully by explaining that he and his friends wanted to get sick in order to miss school. And they failed in this mission.

And we other boys, who would have sacrificed ten terms of our school-life for the sake of being ill for a day … couldn’t catch so much as a stiff neck. We fooled about in draughts, and it did us good, and freshened us up; and we took things to make us sick, and they made us fat, and gave us an appetite. Nothing we could think of seemed to make us ill until the holiday began. Then, on the breaking-up day, we caught colds, and whooping cough, and all kinds of disorders, which lasted till the term recommenced; when, in spite of everything we could manoeuvre to the contrary, we would get suddenly well again, and be better than ever.

The first irony here is that the boys were trying to get sick and could not, except when the holidays came. The second irony is that they were trying to be like Stivvings, in a way. But in the wrong way. If the boys had spent as much time and diligence on their studying instead of finding ways to get out of it, they would probably have gotten higher marks in school. A third irony is the fact that J. is telling this story at all, given what he revealed to us about his own hypochondria and susceptibility to perceived illnesses in Chapter I. J. weaves wry humor into all of his stories.