Scrapie
The name scrapie is derived from one of the clinical signs of the condition, wherein affected animals will compulsively scrape off their fleeces against rocks, trees, or fences. The disease apparently causes an itching sensation in the animals. Other clinical signs include excessive lip smacking, altered gaits, and convulsive collapse.
Crapaud
Jean Crapaud, also Johnny Crappeau or Johnny Crappo, as defined by "Webster's Online Dictionary", "is a jocose name given to a Frenchman. It is intended as a national personification of the French people as a whole in much the same sense as John Bull is to the English. It is sometimes used as a literary device to refer to a typical Frenchman, usually in the form of "Monsieur Jean Crapaud"." The usage of the word "crapaud" in this case is similar to the derogative use of the word "frog", referencing the supposed French affinity for frog legs as a delicacy, and thus considered to be a slur and derogative.