The goose represents the German army marching into the Rhneland in 1936.
There is a simple explanation of the cartoon on this site:
http://www.geocities.com/larwilson2001/germany.htmThere s a good image of the picture on this site -
http://www.education.gpg.gov.za/matricinfo...50321D(eng).doc - where you can see thegoose trampling on the Locarno Treaty (the cartoonist was saying that Hitler's invasion of the Rhineland broke thterms of the treaty), and carrying in its mouth a label saying 'Pax Germanica' (the 'German Peace'). This is an allusion to the 'Pax Romana' - the peace brougt to Europe by the Roman Empire - it is comparing unfavourably the 'peace' brought by German militarism to that brought by the Roman Empire.
Ernest Howard Shepard of course is the man who drew the illustrations for Kenneth Grahame and A A Milne for The Wind in the Willows and Winnie-the-Pooh. But he was also a politicla cartoonist and this is regarded as his best (and funniest) political comment.