I am an emu, and I am one of the lowest members of the class of emetics, or sickening

I am a servant of the public, and my name is Emetic. I produce a puking, which is an operation of great use to the community, in certain circumstances.…

I am a horse, belonging to a circle of friends, who have resolved to bear you on the back, at the rate of eight miles a figure-circle, and to deliver you safely within the limits…