An apparatus made from barrels played an important public health role in the early 20th century.

What is the name of the apparatus shown in these photos ?

Where and when was it used?    What was it used for?

There is a clue in the second photo which is a reconstruction, not the original,  made by the National Museum of Valjevo,

the photos are taken from http://www.valjevo-hospital.org/  with permission.