Winnebago Mental Health Institute still has patient records back to the beginning in the early 1870s when it was named Northern Hospital for the Insane. And in between it was Winnebago State Hospital and a couple other variations.The cemetery is still there; most graves ahve no markers.You can still get info on your ancestor IF you explain your relationship etc. They are reasonable about this. That is, they will not insist on a birth certificate for great-grandma's child when birth certificates were not required and seldom filed in WI at the time.If there was an obit printed, send a copy. Or, if the newspapers or court records give you why he was sent etc. Just "Winnebago WI 54986" should be enough address (On second thought recheck that ZIP code, I did it out of my head). And remember folks were committed back then for postpartum depression, Alzheimers or whatever. Many things we'd handle with a prescrioption these days.