Hans Castorp calculates the yearly cost of staying at the sanatorium and finds it is well within his means -- not that he admits even to himself that he did the sums on his own behalf.
It is half a week until Castorp's expected departure, and he has caught a severe cold. The cold drives the story in this section, from his encounter with Fraulein von Mylendonk, his acquisition of a thermometer, his discovery of his fever, and the overknowing and apparently mistaken reaction of his tablemates (who suggest and perhaps think he really has tuberculosis) to Castorp's decision to have an examination, the seemingly challenging look from Madame Chauchat as he is thinking about skipping it, and the final revelation of his diseased state.
Hans Castorp has trouble with time and the thermometer -- at first time goes too slow, and he can't seem to get to the end of the seven minutes. Then he daydreams a little, and the time goes by so quickly that he is already more than a minute over before he realizes it.
Castorp on Hofrat Behrens, and himself (thinking, I guess, of his odd relationship with Madame Chauchat), 174-175: "Settembrini said his joviality is forced, and one must admit that Settembrini has his own views and knows whereof he speaks. I probably ought to have more opinions of my own, as he says, and not take everything as it comes, the way I do. But sometimes one starts out with having an opinion and feeling righteous indignation and all that, and then something comes up that has nothing to do with judgments and criticism, and then it is all up with your severity, and you feel disgusted with the republic and the bello stile --"
6 hours ago