“Take a course in good water and air and in the eternal youth of Nature you may renew your own. Go quietly, alone no harm will befall you.”

“Man has, as it were, become a kind of prosthetic God. When he puts on all his auxiliary organs, he is truly magnificent but those organs have not grown on him and they still give him much trouble at times.”

“Learning never exhausts the mind.”

“We’re just in the beginning stages of what will be a truly remarkable breakthrough for most people — as remarkable as the telephone.”

“This console here was the best part of my life. And I spent almost 10 years at this console. It is my life, it will always be my life. And I will never leave it behind.”

“If anyone is crazy enough to want to kill a president of the United States, he can do it. All he must be prepared to do is give his life for the president's.”