True, but I think he suffered from multiple sclerosis as well!
JB
No, he had arteriosclerosis, aka hardening of the arteries. That's a condition that can be caused by smoking, high cholesterol, or high blood pressure, and Hartnell probably had all of the above. Multiple sclerosis is an entirely different condition, an autoimmune disorder that attacks the central nervous system, caused by genetic and unknown environmental factors. Both conditions involve abnormal plaques or lesions (sclerae) forming on the anatomy in question, but in a different way and having different effects.
C'mon, "common knowledge" isn't a source. I was looking for something more concrete. The media might have treated scifi shows as kid stuff, and Lost In Space sure was forced in that direction (if Cash Markman is to be believed) but that doesn't mean that the makers intended all those shows to be that. Early Voyage to the Bottom of the Sea sure doesn't seem to be aimed at kids, being more serious and espionage oriented.
I'm sorry, but I've never needed to track down a source for something that's been everyday knowledge for me for most of my life. I'm surprised you'd even question it -- it never occurred to me that it wasn't common knowledge.
Anyway, just look at the time slots.
Voyage started on Mondays at 7:30, then moved to Sundays at 7:00 for the rest of its run, with
Land of the Giants taking over its Sunday time slot when it ended.
Lost in Space aired Wednesdays at 7:30. Those were family viewing hours, airing early enough that kids could watch them before bedtime. Only
The Time Tunnel aired in a later slot, Fridays at 8:00 -- still early enough for younger viewers, though.
But
Lost in Space certainly didn't need to be "forced" in the direction of being child-friendly. Heck, it was explicitly based on
The Swiss Family Robinson, a well-known work of children's literature which was made into a Walt Disney film in 1960. It was originally going to be called
Space Family Robinson, but it had to change its name because there was already a Gold Key comic by that title (and you can look that up on Wikipedia). It was always meant for children. Yes, of course LiS was pushed in a sillier, campier direction than it started out, but that's a totally different matter from whether it was made with young viewers in mind. Kids like serious adventure stories as much as anyone does. They like thrills and suspense and danger, and they take it quite seriously. (Heck, that was the brilliance of
Batman '66. Adults could tell it was a spoof and a comedy, but kids took it in earnest as a superhero adventure, so both audiences could enjoy it on totally different levels.) So just being serious doesn't mean something was meant for adults only. Heck, being a child is very serious business. Just about everything in a kid's life is a matter of worldshaking importance to them.