a yin. On the other hand, a cold treatment would treat a person who is a yang. The next major influence to traditional Korean medicine is related to Sasang typology (사상의학). Yi Je-ma and his book, The Principal of Life Preservation in Oriental Medicine (東醫壽世保元, 동의수세보원) systematically theorized with the influence of Korean Confucianism and his clinical experiences in Korea. Yi Je-ma said that even if patients suffer the same illness, patients need to use different herbal applications to treat the same illness due to the pathophysiologies of individuals. He stresses that the health of human body had a close relationship with the state of mind. He believed that the human mind and body were not separate and they closely reflected each other, and the aspect of mind needed to be considered when examining the causes of disease. Thus, not only food and natural environment but also emotional changes in humans can be another major reason for illness. He believed that medical diagnosis and treatment should be based on person's typology rather than on symptoms alone and each person should be given different prescriptions depending on the constitution of the individual. Sasang typology (사상의학) focuses on the individual patients based on different reactions to disease and herbs. Treat illness by the treatment of the root cause through proper diagnosis. Key to this diagnosis is to first determine the internal organs or pathophysiology of each patient. The next recognized individual is Saam, a priest-physician who is believed to have lived during the 16th century. Although there is much unknown about Saam, including his real name and date of birth, it is recorded that he studied under the famous monk Samyang. He developed a system of acupuncture that employs the five element theory. In the late Joseon dynasty, positivism was widespread. Clinical evidence was used more commonly as the basis for studying disease and developing cures. Scholars who had turned away from politics devoted themselves to treating diseases and, in consequence, new schools of traditional medicine were established. Simple books on medicine for the common people were published. Yi Je-ma classified human beings into four main types, based on the emotion that dominated their personality and developed treatments for each type: Tae-Yang (태양, ) or "greater yang" So-Yang (소양, ) or "lesser yang" Tae-Eum (태음, ) or "greater yin" So-Eum (소음, ) or "lesser yin" The Japanese took control of Korea, which