If we consider the amount of information we can obtain from someone's words as "1," then the amount of information we can obtain from saliva is an astonishing "200 million." It is said that people find the scent of someone with a different immune system (MHC genes) pleasant, increasing the likelihood of producing healthier offspring. Kissing is also a means of exchanging scent information, and we instinctively choose our partners. Being licked all over our bodies and enveloped in saliva...