While some people are allergic to horsehair, others say the allergies are either to horse dander on actual horses or contact allergies where skin makes contact with the hair. Many mattress makers promote horsehair as the finest material anyone can have in a mattress or piece of furniture. The hairs are stiff and hollow and provide unparalleled firmness while acting as insulators and keep the stuffing dry. And apparently, Angelina Jolie sleeps on a $65,000 mattress made of horsehair. Okay, that last bit of info just proves that Google can lead us to too much information on any topic.
So in the name of historical integrity, the awesome weirdness of having furniture containing horsehair, the green bonus of not disposing of the old stuffing, and totally buying into a claim that horsehairs act as "little air conditioners," I'm going to stick with the original innards. Next, I'll post pics of said innards as we begin to take the chair apart. Fun!