The situation with regard to insulin is particularly clear. In many parts of the world diabetic children still die from lack of this hormone. ... [T]hose of us who search for new biological facts and for new and better therapeutic weapons should appreciate that one of the central problems of the world is the more equitable distribution and use of the medical and nutritional advances which have already been established. The observations which I have recently made in parts of Africa and South America have brought this fact very forcible to my attention.
I now know, by an almost fatalistic conformity with the facts, that my destiny is to travel...
And yet on that bench at Jacobacci, I was glad I had left everyone else behind. Although this was a town with a main street and a railway station, and people with dogs and electric lights it was near enough to the end of the earth to give me the impression that I was a solitary explorer in a strange land. That illusion (which was an illusion in the South Pole and at the headwaters of the Nile) was enough of a satisfaction to me to make me want to go forward.
Thus was this expedition finished...after having, by its event, strongly evinced this important truth; that though prudence, intrepidity and perseverence united are not exempted from the blows of adverse fortune, yet in a long series of transactions they usually rise superior to its power, and in the end rarely fail of proving successful.Voyage Around The World, 1751