Sanatorium???

I've been going through some documents that a family member sent to me.  There are letters that my Great Grandfather, William Adam Jackson Loyd, wrote to his wife, Ada Grant.  It didn't occur to me to even question why they were apart or where he was writing from.  But those questions occurred to me as I continued to read the letters.  I finally got to a post card that William sent to one of his daughters, with a picture of the State Sanatorium on the front.  What is a Sanatorium??  I had no idea what it was.  So I googled it.  Here is the information I found. Thank you Charlotte Brown for posting your family pictures!!  I guess my Great Grandfather was being treated for TB when he wrote these letters to my grandmother in 1947, about a year before he died.