Research Article Varieties of smoke. Br Med J 1972; 3 doi: https://doi.org/10.1136/bmj.3.5817.50-a (Published 01 July 1972) Cite this as: Br Med J 1972;3:50 Article Related content Metrics Responses Peer review This article has a correction. Please see:Dr. I. J. Sachs - July 13, 1974 This is a PDF-only article. The first page of the PDF of this article appears below.