Contained within the 3rd Edition (1957) of the Atlas of Canada is a map that shows a map of three condensed maps of the location and capacity of Canadian hospitals circa 1951. The largest map shows the pattern for general hospitals, which are hospitals treating basically all forms of illness. The second map shows mental hospitals, which are institutions where psychiatric disorders are treated. The third map shows special hospitals - these are institutions treating particular types of illness such as chronic conditions, and those treating communicable diseases (such as sanatoria for tuberculosis). All maps use similar mapping formats. Part of this format is the use of a single symbol to combine the bed totals for all hospitals of the particular type in a single city.