What would D.O.R.A. have meant in 1929?

I recently started reading a strange little book from 1929 called Breaking Priscian's Head, or English as She Will Be Spoke And Wrote, by a Scotsman named J. Y. T Greig. In a passage about how some words drop out of the language because the things they describe are no longer in use, Greig mentions the words "hansom", "four-wheeler", and "D.O.R.A.", expressing considerable happiness at the disappearance of that last one.

So, it turns out that Greig was absolutely correct about the disappearance of "D.O.R.A", and I haven't the faintest clue what it could possibly mean. A quick Google search yields nothing that seems applicable to the 1920s. Do any of you have any ideas?

Here's a picture of that page, by the way:

What did you put in your Google search? I typed D.O.R.A. and found the Defence Of the Realm Act.

Seems to have been finally repealed in 1927. Looks right to me. I think this question will be closed for insufficient research, it took me two minutes to find out what it was and another five to find out when it was repealed. (The UK parliamemt website not being keen to tell me that, perhaps it's a state secret)