Very interesting set of pictures from Iowa University Hospital including one of a pretty rare looking early motorized ambulance.... perhaps electric? and a lot of sedan ambulance shots... they had a big fleet that would rival many modern services in size!
http://www.flickr.com/photos/uiowa/sets/72157631652105200/with/8036771821/
http://www.flickr.com/photos/uiowa/sets/72157631652105200/with/8036771821/