It takes a certain specialist's dedication to travel in squalid cities and fetid slums, among the utterly dependant poor, who have lost nearly all of their traditions, and most of their habitat. You need first of all the skill and the temperament of a proctologist. Such a person, deft in rectal exams, is as essential to medicine as any other specialist, yet it is only the resolute few who opt to examine the condition of the human body by staring solemnly - fitted out like spelunkers, with scopes and tubes and gloves - up its fundament and trawling through its intestines, making the grand colonic tour. Some travel has its parallels, and some travellers might fit the description as rectal specialists of topography, joylessly wandering the guts and entrails of the earth and reporting on their decrepitude. I am not one of them.