Threads of History

I’ve begun reading George III, A Personal History, by Christopher Hibbert.  One of those fun little tidbits of history was revealed on the 8th page. 

... the future King George III, was born on 4 June 1738 at a home in St. James’s Square rented from the Duke of Norfolk.

and in the footnote:

Norfolk House was demolished in 1938 and the present house, No. 31, was built on the site to the design of Messrs Gunton and Gunton.  A plaque on the front of the building records that it was there that General Eisenhower formed the first Allied Force Headquarters, and planned the North African campaign of 1942 and the invasion on north-west Europe in 1944.  There is no plaque recording the birth of King George III.

How fitting. 

On an unrelated note, on page 43 the author is relating the voyage of the future queen to England.  It references two of her companions as such:

These were the Duchess of Ancaster, her Mistress of the Robes, and the Duchess of Hamilton, First Lady of the Bedchamber, the discomfort of the first being exacerbated by her being pregnant and ‘subject to hysteric fits’, and of the other by concern for the lactation of the ass that she had insisted on taking aboard with her.

I googled “lactation of the ass” and the results were… unpleasant.  Surely there is another meaning, but I can’t seem to uncover it.  Does anyone know?