S1·E25 Milking Cows

Archie wants to show the nursery children his latest invention- a milk dispenser. Miss Hoolie says that he should show them where milk comes from in the first place. He knows that Milk comes from cows, so he borrows a model of a cow from Edie McCredie. But he still doesn't know exactly how cows are milked, so he needs to see P.C. Plum.