Who said "Kindness toward all living things is moral duty"?

This quote is attributed to Hugo de Vries.

Kindness toward all living things is moral duty - Hugo de Vries

"Kindness toward all living things is moral duty"

Hugo de Vries Kindness

Botanist and Geneticist Dutch 1848–1935

"Mutation is the only source of novelty in evolution"

"Nature does not proceed by leaps"

"The origin of species lies in the nature of variation"

"Evolution is a process of continuous change"

"A good man treats his wife with respect."

"Kindness always comes back around."

"The power of a smile can change everything."

"Kindness is weakness to some. Not to me."