That's a neat bottle I havent seen before. I think its Dilworth rather than Dillworth.
Looks like somewhere between late 1880s and 1890s. What region did it come from?
I am thinking it is some type of local (to your area) med for animals. Were ever you pick it up from? What area? Thats how I would trace it back. Looks to be 1870's with the deep mold panels in the bottle.
Most worm meds were for human consumption...folks did not seem to be too concerned with wormy animals....at least not until we started keeping dogs as pets and not as work animals.
Just realized I hadn't looked.in my Delaware medicine list and I found a E.T. Dillworth bottle from Wilmington Delaware in there. Funny because its spelled with 2- LL's just like I misspelled it. I'm guessing this is a Delaware bottle. Will have to do some more research.