Fit as Fiddles and as Hard as Nails

[1 January [1916]] Ive just opened a parcel now & thank you awfully dear for all the nice things it contains. The French book has grand big print which is a great thing. I must tell you we are your plum pudding last night it was fine: it was merged in with those of others in a big pudding.
I am writing this to Paris I expect it’ll catch you OK.