REVIEWSBr Med J 1931; 1 doi: https://doi.org/10.1136/bmj.1.3672.899 (Published 23 May 1931) Cite this as: Br Med J 1931;1:899
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