"Man is the masterpiece of creation."

"Whoever wishes to be a good botanist must be a good observer."

"Yet man does recognise himself [as an animal]. But I ask you and the whole world for a generic differentia between man and ape which conforms to the principles of natural history, I certainly know of …"

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

"The more I collect and examine, the more I marvel at the infinite wisdom of the Creator."