Fictional Detectives: Agatha Christie's elderly female crimesolver.?

Questions

what are cocci, spirilla and streptococci?

Eddie and his father's last name in "The Courtship of Eddie's Father"?

Edgar allan poe introduced mystery fiction's first fictional detective, auguste c. dupin, in what 1841 story?

Edgar allen poe wrote a famous poem about which animal?

A complex alcohol constituent of all animal fats and oils?