Гэ Хун
According to Ge Hong, a 4th-century Taoist alchemist, "those seeking 'immortality' must perfect the absolute essentials. These consist of treasuring the jing, circulating the qi and consuming the great medicine." The sexual arts concerned the first precept, treasuring the jing. This is partially because treasuring the jing involved sending it up into the brain. In order to send the jing into the brain, the male had to refrain from ejaculation during sex. According to some Taoists, if this was done, the jing would travel up the spine and nourish the brain instead of leaving the body. Ge Hong also states, however, that it is folly to believe that performing the sexual arts only can achieve immortality and some of the ancient myths on sexual arts had been misinterpreted and exaggerated. Indeed, the sexual arts had to be practiced alongside alchemy to attain longevity. Ge Hong also warned it could be dangerous if practiced incorrectly.