Plumbing vent help

Hey Guys,

100 yr old house today. The only plumbing vent i could find was this valve in the basement. Not sure if it’s some kind of check valve that lets air in, but also keeps the sewer gas from escaping. The pipe in back, you can only see half of is 6" long and open. Any help would be appreciated.

529 Elm St. wabash 062.jpg

It almost looks like a drum trap to me. I don’t see how it would vent.

I agree not seen much any more . Roy Cooke sr.

Well I’m not sure either. I didn’t have any water on this property, so i couldn’t flush the toilet or check any drains. Everything is evidently venting through this. Dang, you got to love old houses. Thanks for the replies.