An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Pratt TA, Frew HW.Pratt TA, et al.Br Med J. 1929 Mar 30;1(3560):595-6. doi: 10.1136/bmj.1.3560.595.Br Med J. 1929.PMID: 20774576Free PMC article.No abstract available.
Pratt TA, Frew HW.Pratt TA, et al.Br Med J. 1931 Apr 11;1(3666):622-3. doi: 10.1136/bmj.1.3666.622.Br Med J. 1931.PMID: 20776114Free PMC article.No abstract available.