Mencken on professor

Professor , like doctor , is worked much less hard in England that in the United States. In all save a few of our larger cities every male pedagogue is a professor, and so is every band leader, dancing master, and medical consultant. Two or three generations ago the title was given to horse-trainers, barbers, bartenders, phrenologists, caterers, patent-medicine vendors, acrobats, ventriloquists, and pedagogues and champions of all sorts. Of late its excessive misuse has brought it into disrepute, and more often than not it is applied satirically. The real professors try hard to get rid of it.

H. L. Mencken, The American Language: An Inquiry into the Development of English in the United States, 4th ed. (New York: Alfred A. Knopf, 1936).

Also from The American Language
The American v. the Englishman : “Are you a speed-cop?” : B.V.D. : English American English : “[N]o faculty so weak as the English faculty” : Playing policy : “There are words enough already” : The -thon , dancing and walking : The verb to contact