"Inventing the Feeble Mind"

I'm reading Inventing the Feeble Mind: A History of Mental Retardation in the United States right now, and I'm struck by James Trent's lengthy discussion on mental "idiocy" in the 19th century. Which has me thinking about a couple things:

1. "Crisis" or "epidemic" rhetoric of autism is reliant on autism as a construction of 20th-21st century epidemiology. Autism has to be caused by mercury, pollution, toxins... But...
2. One could look at archival material of "idiocy" in 19th century, if one were so inclined, to "identify" autistic individuals in 19th century using 20th century diagnostic criteria. While this isn't something I necessarily want to do in my dissertation, it's a relevant point and one that could be further explored in a lengthier study.
3. If autism did exist in 19th century (as I believe it did) then why the need to begin any history of autism with Kanner in early 20th century? Why not go back and look at archival research of "idiots" in America in 19th century? "Idiots" existed. So, why does "autism" only begin with Kanner? My answer: ease of accessibility. If one were to look at archival material/records of "idiots" and their behaviors in 19th century, that would be a HUGE undertaking. Enormous. (Maybe a smaller analysis would be appropriate for a chapter/section of one's dissertation?) But, to do a comprehensive exploration of autism and mental impairment in the 19th century? That's a huge undertaking. One reason being the accessibility of records and documents. BUT to look at 20th century cases of autism? Not as hard. One, the diagnostic criteria exists already. Two, media. **We don't know about what we don't know about. **

Just some thoughts I was bouncing around in my noggin this morning...