There is one other part of Letter 21 that has, upon further examination, caught my eye, for a couple of reasons, which quickly led me to an extraordinary satirical Biblical allusion! It is the first paragraph on p. 4 of Letter 21:
" "On more accounts than one you wished our stay here to be lengthened beyond last Thursday." There is some mystery in this. What have you going on in Hampshire besides the _itch_// from which you want to keep us?"
There was something about the phrase "the itch from which" which sounded like Ogden Nash to me, and I also had a flash of our own Internet discussions of JA, when JA actually quotes a sentence from CEA's previous letter (I cannot recall JA doing that in any other real life letter, or in any of the letters which her characters writer in her novels), and then comments on it. And it seems like JA is just horsing around with "There is some mystery in this", suggesting that CEA might have some mysterious intrigue going on at Steventon that would benefit from a few more days of privacy. All standard JA absurdist fantasy.
But, as I always do when I get a hunch, I asked Google to tell me if there might be something more, and look where Google took me, a modern version of Deuteronomy, 28:27, stating one of the many curses for disobedience of God's laws:
"The LORD will smite you with the boils of Egypt and with tumors and with the scab and with _the itch, from which_ you cannot be healed."
Wow! Now that is interesting, because it fits so well--if JA is playfully suggesting that CEA may be engaged in some mysterious activity which constitutes disobedience of God's laws, then the joke is expanded by JA suggesting that CEA wants to keep JA and the rest of the family from returning home and somehow getting involved in CEA's miscreancy, so that they won't be cursed with the itch from which you can't be healed!
There is one caveat, which is that in the language of the Bible contemporary with JA's time (following the King James version in this regard), 28:27 was translated as follows:
"The Lord will smite thee with the botch of Egypt, and with the emerods, and with the scab, and with the itch, whereof thou canst not be healed."
But I think that JA, whether she rewrote the Biblical verse on her own to create a rhyme, or read this alternative phrasing "itch from which" somewhere else, was indeed making a veiled and satirical Biblical reference to Deuteronomy 28:27.
And what makes that a certainty in my mind, and perhaps in yours as well, is the completely hidden, multi-layered connection between the above quoted lines from JA's Letter 21, and the following lines which she wrote later in that same Letter 21:
"Now I will give you the history of Mary's veil, in the purchase of which I have so considerably involved you that it is my duty to economise for you in the flowers. I had no difficulty in getting a muslin veil for half a guinea, and not much more in discovering afterwards that the muslin was thick, dirty, and ragged, and therefore would by no means do for a united gift. I changed it consequently as soon as I could, and, considering what a state my imprudence had reduced me to, I thought myself lucky in getting a black lace one for sixteen shillings. I hope the half of that sum will not greatly exceed what you had intended to offer upon the altar of sister-in-law affection."
So we are back on Mary Austen again, this time with JA's sarcasm about the gift of a fruity hat to their not-very-beloved sister-in-law, which JA and CEA are going halves on. The connection back to "the itch from which" is in that last phrase "offer upon the altar of sister in law affection".
Check out what it says in Deuteronomy 27:6-7, which is when the section about curses for disobedience actually begins:
"You shall build _the altar_ of the LORD your God of uncut stones, and you shall offer on it burnt offerings to the LORD your God; and you shall sacrifice peace offerings and eat there, and rejoice before the LORD your God."
Is it just a coincidence that JA concocts a metaphor of an offering of fruit upon an altar a few sentences after mentioning "the itch from which" CEA wants to keep JA? I don't think so!
And the icing on the cake (or should I say instead, the Orleans Plum on the hat?) is the following in Deuteronomy 28: 30 (i.e., only three verses after "the itch from which"!):
"You shall betroth a wife, but another man will violate her; you shall build a house, but you will not live in it; you shall plant a vineyard, but you will not use _its fruit_.
This is JA having a wickedly good time painting a satirical portrait of her sister in law Mary Austen, who, I would imagine, was a sanctimonious prig, by casting Mary as the Lord to whom the rest of the Austen family, being mere Israelites, must offer fruity peace offerings to appease Mary's wrath and avoid her curses! And it is even more edgy, because the curse of 28:30 seems to refer to Mary as a recently betrothed wife, suggesting not very nice things about the siring of baby James Edward Austen!
Jane Austen and William Cowper
1 day ago