english: To support this theory, Cartwright helped to perfect a medical device for measuring breathing called the spirometer to show the presumed deficiency in black people's lungs.
non_english: Da bi potkrepio ovu teoriju, Kartrajt je potpomogao usavršavanje medicinske naprave za merenje disanja zvane spirometar da bi pokazao pretpostavljeni nedostatak u plućima ljudi crne rase.