"My husband and I were so closely united by our affection and our common work that we were not afraid of anything, even of the difficulties of a material existence."

"The way of progress was neither swift nor easy."

"We must believe that we are gifted for something, and that this thing, at whatever cost, must be attained."

"I was very much absorbed in the study of physics and chemistry."

"The scientist in his laboratory is not merely a technician, but also a child confronting natural phenomena that impress him as though they were fairy tales."