A brief but invaluable account of kissing appears in the American Journal of Medicine, timed for the ‘marital month of June’.
Philematology is the name of this new science: “during kissing, couples exchange an average of 9ml of water, 0.7mg of protein, 0.18mg of organica compunds, 0.71mg of different fats, and 0.45mg of sodium chloride. As many as 10 million to 1 billion bacteria representing 278 different species may be exchanged during an active kiss, with 95% of these organisms classified as nonpathogenic for individuals who are immunologically competent.”
A ‘however’, inevitably follows, although the author – who is also the journal’s editor – concludes that “despite potential risks, this common practice will continue to be performed in the future by human beings throughout the world.”
Source: American Journal of Medicine 2013, doi:10.1016/j.amjmed.2012.12.022.