IF PARENTS PASS ENTHUSIASM ALONG TO THEIR CHILDREN, THEY WILL LEAVE THEM AN ESTATE OF INCALCULABLE VALUE

Personally, I enjoy working about 18 hours a day. Besides the short catnaps I take each day, I average about four to five hours of sleep per night.

If I had not had so much ambition and not tried to do so many things, I probably would have been happier, but less useful.

X-rays ... I am afraid of them. I stopped experimenting with them two years ago, when I came near to losing my eyesight and Dally, my assistant practically lost the use of both of his arms.

I think work is the world's greatest fun.

Be brave as your fathers before you. Have faith and go forward.

I have never seen the slightest scientific proof of the religious ideas of heaven and hell, of future life for individuals, or of a personal God.