"He paused and put his hand to his throat, and I could see,
in spite of his collected manner, that he was wrestling against the approaches of the hysteria."
Here, it is evident as to just how determined Utterson was to discover the truth in terms of Jekyll, however, he represses this excitement which is emphasised by the use of the word "hysteria" which links to an almost erratic amount of excitement. He represses these feelings in order to come off as calm and collected.