until now , the sang-froid with which he had conducted himself in these conditions was dependent on a kind of self-assurance that was not only therapeutic to him but also allowed him to maintain the psychological distance that he sought with respect to the other inmates and , therefore , it was now disheartening to have this equanimity that hed afforded himself shattered by the appearance of an insignificant little creature who had taken it upon itself to reside somewhere upon his person .