Epidemiology SectionBr Med J 1948; 2 doi: https://doi.org/10.1136/bmj.2.4574.503 (Published 04 September 1948) Cite this as: Br Med J 1948;2:503
Log in using your username and password
Log in through your institution
Register for a free trial to thebmj.com to receive unlimited access to all content on thebmj.com for 14 days.
Sign up for a free trial