The passage discusses the surgical treatment of rotary-lateral curvature of the spine, as addressed by Dr. Teschner. He identifies four key factors in the etiology of the condition: hereditary tendency, general temperament and mental state, lack of muscular development, and habitual faulty positions. Dr. Teschner categorizes the deformity into three degrees: (1) "habitual" curvatures that can be corrected by voluntary muscular efforts, (2) curvatures that can be reduced by suspension, and (3) curvatures that cannot be corrected even by suspension. For each category, he outlines specific treatment methods, including rest, self-suspension, exercises, and the use of specialized equipment. The passage also mentions the importance of improving general health and the role of fresh air and, for children, removing them from school if necessary. Additionally, it touches on the educational aspects of the book, emphasizing the study of the individual child and the application of psychological principles in education.The passage discusses the surgical treatment of rotary-lateral curvature of the spine, as addressed by Dr. Teschner. He identifies four key factors in the etiology of the condition: hereditary tendency, general temperament and mental state, lack of muscular development, and habitual faulty positions. Dr. Teschner categorizes the deformity into three degrees: (1) "habitual" curvatures that can be corrected by voluntary muscular efforts, (2) curvatures that can be reduced by suspension, and (3) curvatures that cannot be corrected even by suspension. For each category, he outlines specific treatment methods, including rest, self-suspension, exercises, and the use of specialized equipment. The passage also mentions the importance of improving general health and the role of fresh air and, for children, removing them from school if necessary. Additionally, it touches on the educational aspects of the book, emphasizing the study of the individual child and the application of psychological principles in education.