A kiss is a contact, a union, an exchange. It is unknown to certain races and tribes, while others know it and consider it with disgust. They all suffer a loss. A kiss can be a cold formula, or a token of familial relationship or a prelude to the act of love. It can also be a revelation in an unspoken, secret language of feelings that have never been expressed in words.

Harry Harrison (1925-2012) American author [b. Henry Maxwell Dempsey]

The Jupiter Plague, ch. 9 (1982)
    (Source)

The same phrase occurs in the "shorter and substantially different" earlier Plague from Space, ch. 9 (1965).