I handed her a writing-block. Swiftly, with a trembling hand, she jotted down a few figures. Then she stopped and looked at me with eyes full of anguish.
I understood the effort which she had made and, to calm her, said:
"Don't rack your brains now . . . it'll come later. . . . What you need to-day is rest. Go to sleep, my darling."
"I must find it . . . at all costs. . . . I must. . . ."
"You'll find it some other time. You are tired now and excited. Rest yourself."
She did as I said and ended by falling asleep. But an hour after, she woke up, took the sheet of paper again and, in a moment or two, stammered:
"This is dreadful! My brain refuses to work! Oh, but it hurts, it hurts! . . ."
The night was spent in these vain attempts. Her fever increased. Next day she was delirious and kept on muttering letters and figures which were never the same.
For a week, her life was despaired of. She suffered horribly with her head and wore herself out scribbling lines on her bed clothes.
When she became convalescent and had recovered her consciousness, we avoided the subject and did not refer to it for some time. But I felt that she never ceased to think of it and that she continued to seek the formula. At last, one day, she said with tears in her eyes: