Antique surgical Amputation Saw dating from the early 20th century and by Down Brothers of London. The handle is chromed, the blade steel, good solid condition with surface wear and some tarnish.  The saw measures 21cm (8.27") in length.
 
There is a similar example as part of the Science Museum Collection in London which can be seen here:
https://collection.sciencemuseumgroup.org.uk/objects/co175145/amputation-saw
 
Medical items such as these were made to the highest quality standards as cost was not the main factor and they were necessarily made in small numbers and so are becoming increasingly rare.