"The progress of science is slow, but it is sure."

"My mind is so completely absorbed in this subject, that I can think of nothing else."

"I have often been accused of being too sanguine in my expectations; but time will show whether I am right or wrong."

"The true philosopher is he who is always learning, and who is never ashamed to confess his ignorance."

"The most beautiful part of the human frame is the eye; and yet it is the most liable to disease."