Johann Baptist von Spix

with the indians who inhabit the hot equable and damp parts of south america the skin apparently does not answer to mental excitement so readily as with the natives of the northern and southern parts of the continent who have long been exposed to great vicissitudes of climate.

For Humboldt quotes without a protest the sneer of the Spaniard, How can those be trusted who know not how to blush? Von Spix and Martius, in speaking of the Aborigines of Brazil, assert that they cannot properly be said to blush.

It was only after long intercourse with the whites, and after receiving some education, that we perceived in the Indians a change of colour expressive of the emotions of their minds.

It is, however, incredible that the power of blushing could have thus originated.