Despite his much repeated claims to be 'the first white man' in the area, Joseph Rock was following in the footsteps of other westerners - missionaries and plant hunters - in the Nujiang/Salween canyon. Here's what the German botanist Heinrich Handel-Mazzetti said of the Nu people he encountered around the mission stations of Baihanluo in 1917:
"The Nu do not practice alpine cattle farming: hence the well preserved state of their forests and the tracklessness of their mountains. They are a Burmese people and according to their handed-down traditions they migrated from the Drong Jiang. Most of them are short and somewhat unprepossessing in appearance, but absolutely honest. They are at a very low level of civilisation. They have no writing and their language is extremely poor in its vocabulary, being without any means of expressing abstract ideas; for example, they had no word for "colour". They do not lock up their houses when they go out, they leave their few cattle unattended on die pastures, they wash as seldom as the other peoples living in these parts, and they are very easily converted to Christianity."
Original account is here.