"The stone grows, the plant grows and lives, the animal grows, lives and feels."

"When the spiritual light is concentrated in the brain, everything else must be sinking in the dark."

"It is not the business of a botanist to know all the plants, but to know how to find out what they are."

"In natural science the principles of truth ought to be confirmed by observation."

"Nature has always been my school, and my teachers have been the trees, the flowers, and the stones."