At the age of 10, Thérèse contracted a strange sickness that, in my opinion, could have come only from the devil due to the spiritual phenomena that occurred. The sickness came to light a few months after Mother Agnès of Jesus joined the Carmel, towards the end of March 1883.
From 7th April to 10th May, the day on which the Blessed Virgin healed her, she remained in a sorry state. Several times a week, she had fits of terror so severe that a learned doctor, Dr Motta [Notta], who is now dead, said he had never come across a case like it. I heard him admit his powerlessness to our father. He even said, “Let people call it what they will. In my opinion, this is not hysteria.”
The plainest of objects would take the form of horrible monsters in her eyes and she would scream with fright.
She was frequently compelled by an unknown force to throw herself head first off her bed onto the flagged floor. At other times, she would violently knock her head against the wood of the bed. At times she would make to speak to me, but no sound would come from her lips. She could only articulate words and not pronounce them.
One detail that I found particularly striking was that on various occasions, under that devilish influence, which is what I believe it was, she would suddenly kneel down, lean her head against the bed and, without using her hands, try to bring her feet forwards. Now, in this unfailingly unladylike posture, she would always remain modestly covered, to my great surprise. Unable to explain it, I attributed it to divine intervention.
Her fits would leave her utterly exhausted.
The most terrible fit of all was the one she mentions in her autobiography. I thought it would kill her. Seeing that her struggle was exhausting her, I tried to give her something to drink, but she cried out in terror, “They’re trying to kill me; they’re trying to poison me!”
It was then that my sisters and I threw ourselves at the foot of the statue of the Blessed Virgin and begged her to have mercy on us. However, heaven appeared deaf to our prayers. I repeated the same prayer three times. The third time, I saw Thérèse stare at the statue of the Blessed Virgin; her eyes beamed, as though she were in rapture. I realized she was seeing not the statue but the Blessed Virgin herself. The vision seemed to last for four or five minutes, then two large tears fell from her eyes, and she gazed upon me lovingly, her expression sweet and limpid. I had not been mistaken; Thérèse was cured. Once alone with her, I asked why she had wept. She was reluctant to share her secret with me, but realizing that I had surmised what had happened, she said, “Because I could not see her anymore.”
Sr. Marie of the Sacred Heart (Marie Martin)
Testimony, Apostolic Process (excerpt)