"There is no firm reason to anticipate that the intellectual capacities of peoples geographically separated in their evolution should prove to have evolved identically. Our wanting to reserve equal powers of reason as some universal heritage of humanity will not be enough to make it so."

yes, that first reaction you just thought is known as a "knee-jerk reaction." just observe it and move on to read the words and understand them as any rational person should. i think in this dr. watson is entirely correct. however we have to understand what we mean by "intellect." if we take out "intellect" and anything related to it and replace it with, hm, something like resistance to xyzitis disease (ok i made up the disease but just walk with me)... the quote then reads something like the following

"There is no firm reason to anticipate that the resistance to xyzitis of peoples geographically separated in their evolution should prove to have evolved identically. Our wanting to reserve equal resistance to xyzitis as some universal heritage of humanity will not be enough to make it so."

it makes sense now doesn't it! people need to stop being so racist and instead think in terms of evolution and natural selection.