Authentic Supplication Number 148.

It is reported by way of `Aa'ishata  that if a person was ailing in some part of his body, or if he had a wound, the Prophet  would do with his finger as such, and Sufyan put the tip of his finger in the ground, then lifted it, and said: Bismillah turbatu 'ardhina, bireeqati ba`dhina, yusfaa saqeemuna, bi'ithni rabbina (167).

Footnotes.
(167) In the name of Allah, the dust of the earth, with the saliva of some of us, our sick is remedied with the permission of our Lord. Al-Bukhari's translation by Hilali and Khan in a footnote says that: While reciting the charm (ruqya) The Prophet  took some of his saliva on his index finger and touched the earth with it and applied the resulting mixture to the place of ailment.

Reporters.
Agreed upon by Bukhari and Musim, and Al-Albani said that it was also reported by Abu Dawood, Ibn Majah, An-Nisa'ee in Al yawmu wa-allailah, and Ibn As-Sunni (#566). Al-Albani included this hadeeth in The Authentic of Good Sayings as #119.