There are three branches of medicine. One is called "doctor medicine" or "scientific medicine". Scientific doctors try to observe sicknesses, look for logical patterns, and then find out how the human body works. From there they figure out what treatments may work. This kind of medicine is believed to date from the 4th century BC. Although nowadays it is successful, in the ancient world this approach probably did not cure many patients.
The second kind of medicine is called "natural cures" or "folk medicine", in which less educated people try to cure sicknesses with various herbs (草药). These folk healers also use observation and logic, but they are not aware of it. They try things until they find something that seems to work, and then they keep doing that. Folk medicine flourished long before the development of scientific medicine and was more successful in ancient times than doctor medicine.
The third kind is called "health spas" or "faith healing". Sometimes this is as as touching the holy man and being immediately healed. Other times, a magician may make you a magic charm, or say a spell, to cure you. Some religious groups organize special healing shrines (神坛) for the sick. In these places people rest, get plenty of sleep, eat healthy food, drink water instead of wine, and exercise in various ways. They also talk to the priests and pray to the gods. If you are feeling depressed or you have been working too hard, going to these places may be just the fight thing to make you feel better.
The author’s primary purpose in this passage is to______.