1827, "to handle skillfully by hand," a back-formation from manipulation. Of mental influence, from 1864. Financial sense is from 1870. In mid-20c., it served as a euphemism for "masturbation." Related: Manipulated; manipulating.
manipulate ma·nip·u·late (mə-nĭp'yə-lāt')
v. ma·nip·u·lat·ed, ma·nip·u·lat·ing, ma·nip·u·lates
To handle and move in an examination or for therapeutic purposes.