Sorry I should have included this text from the book: "An unusual type of hand-made glass measure had a spout and was particularly useful for administering medicine to patients who were unable to sit up". W A Jackson, the author, certainly seems to know his stuff. It wouldn't be the first time the V and A (or any museum) didn't get things right (the curator of the Royal College of Physicians museum did not appreciate me pointing out the difference between cupping glasses and leech pots and the V+A has a leech pot which they just call a "bowl").
best, Julie
PS agree with Christine's comments, you need suction for a pump/reliever (see p. 28 of Jackson's book) whether through a pump/rubber bulb or the long glass tube that the mother could suck on herself (as in the Science Museum image) otherwise if you're just doing a bit by hand a regular cup is more suitable