The hog told those interested all about the damage done to members of his family by the roundworm. During its discussions, the hog would deflate – “as the roundworm gets to work”.
The talking was done by means of a concealed phonograph record and inflation action was accomplished by means of compressed air.
United States Department of Agriculture. The Educated Hog, 1928. Library of Congress and Wikimedia Commons, Public Domain License.