On this date, one hundred years ago...
one of the great tragedies of the Professor's life happened. His mother, Mabel Tolkien née Suffield, died at the age of 34, after spending six days in a diabetic coma. John Ronald Reuel was twelve,while his brother Hilary Arthur Reuel was ten. Their father had died eight years previously.
It was his mother who first began to teach the boy who would become the Professor, and it had been she, a struggling, penniless widow, who had brought herself and her sons into the Church, despite fierce family opposition.
According to a friend of mine, the first person to live a long life with the help of insulin injections began her treatments the next year.

I remember trying to tell Marjorie Incledon (ed. his cousin) this feeling, when I was not yet thirteen after the death of my mother, and vainly waving a hand at the sky saying "it is so empty and cold".

J.R.R. Tolkien to Michael Tolkien, January 24, 1972