1920s, Advertisement Sanborn Company Advertisement, 1924 June 23, 2013 Richard Johnston Leave a comment From the Canadian Medical Journal, 1924, probably the January Issue.
1900s, Advertisement, Drawing, Spirometer Spirometer, Simplex, Advertisement, 1901 June 18, 2013 Richard Johnston Leave a comment From The Alkaloidal Clinic (a Home Health Magazine filled with patent nostrums and gadgets), 1901.
1910s, Advertisement, Drawing, Spirometer Spirometer, Simplex, Advertisement, circa 1918 June 18, 2013 Richard Johnston Leave a comment From: http://www.flickr.com/photos/38987873@N00/4101368319/sizes/o/in/photostream/