"The American is obstinate, contented, free. He paints himself with red lines and is regulated by custom."

"¿Qué tiene de extraño que yo no vea a Dios si no puedo ver siquiera al Yo que vive en mí?"

"If you do not know the names of things, the knowledge of them is lost, too."

"Every plant is a book, which, if we want to understand, we must learn its language."

"The aim of natural history is to know God in His works."