Apparently written by Anais Nin (imagine the umlaut in there) in the fall of 1943, and posted by a friend on Facebook. What's interesting about the word here is that 1.) It's coined and 2.) Dislocated from what sounds like a medical context, it looks kinda funny--and it looks as if it sounds like celery.
Given its etymological links to small rooms (such as monastic cells), brain compartments, and the uterus, the children's book The Diamond in the Window, by Jane Langton, comes to mind. In the story, a brother and sister escape from a chambered nautilus (yes, they're are trapped inside a shell) by thinking their way out.
There's also an obvious joke to be made about cellular phones, and a less obvious point to be made about the current rage for All Things Brain. People who subscribe to the trend that is All Things Brain will likely read in this passage a literal interest on Nin's part in the cellular. I would like to believe that she was referring more to mind than she was to brain. I imagine her set of metrics would be more valid than science can allow.
There are very few human beings who receive the truth, complete and staggering, by instant illumination. Most of them acquire it fragment by fragment, on a small scale, by successive developments, cellularly, like a laborious mosaic.