On the window sill, in amongst the frightening assortment of false teeth and tools of the trade, appears to be a bottle of carbolic salve, a common pain medication of the era. Those interested in experiencing dentistry of the past could purchase some "J.R. Watkins Petro-Carbo Salve", still available on Amazon and elsewhere, and ask their dentist to use that instead of novocaine. Recommended only for the most masochistic of patients.

I'm sure Dr. Johnston spared no pains when treating his patients.

Even with all the modern dental technology, new methods of sanitation and more efficient instruments, removing a single deeply-rooted tooth (from the lower back of a patients's mouth for example) still requires lots of novicaine, the dentist's brute strength and a pair of pliers. Just think happy thoughts.

Perhaps surprising to some, many of the basic instruments (the first thing you learn in dental school is they are not tools!) are still in use in most dental offices today. Today's offices are a interesting mix of 100-year-old instruments along with lasers and in office cad/cam abilities. By the way, the bulbous thingy on the chair tray gives the dentist ( pre-air compressor times) a way to blow tooth dust and/or excess amalgam off the tooth being treated. The Caulk company box by the window is still a major supplier to dentists.

Note the need to face the window to get enough light on the subject. Trying to see inside someone's mouth with a feeble 1919 electric lightbulb in the ceiling can't have been easy. How they did it by gaslight I don't know. This may be why other Shorpy examples of 'Painless Potter' are situated on the higher floors of buildings.

if you lay all the instruments out on the window sill?

How reassuring.

from the late Steam Punk era always look so much more sinister than modern ones--almost looks like a trocar hanging in front of the window and those clamps and scissors, ugh!

I remember chairs and setups such as this when living in the Philippines 50 years ago. Would have been a tad bit more sanitary with the instruments on a tray or table next to the chair. My father would tell other horror stories about pedal powered drills. At least I did not have to go thru that.

What is spattered all over the wainscoting ?

The wall seems to be splattered with something. You might think the dentist would clean it.

Overall, this looks like a chamber of horrors, compared to a modern dentist's office, where the instruments of torture are kept (mostly) out of sight.

You can see the scuff marks on the wall from flaying feet during a procedure -- last patient "I'm outta here!"

It would be 'Painless' I presume.

A case could be made for YPROHS instead of SHORPY to have been engrained onto this image, given the title chosen by Shorpy.