"The perpetual sweet-eating habit practiced ... is so harmful to them that parents should adopt the 'out of sight out of mind' policy as far as lollies and chocolates are concerned." The book then goes on to say that a barleysugar or boiled sweet is fine occasionally, but toffees and other "sticky jawy" things should never be eaten.
My first thought when reading this (once my guilt at giving my son the odd sweet treat and enabling his current addiction to peanut butter and honey sandwiches subsided) was: where do gummy lollies sit in the hierarchy of evil sweets? You know the kind, the delicious lollies that are usually brightly coloured and shaped like non-sweet things. Like, fried eggs. Or worms. Or teeth, in some sort of perverse homage to the thing that the treats are rotting.
I've heard before that gummy lollies are worse than chocolate because the gummy bits stick between teeth. I tried to find out via Google, but was so overwhelmed by photos of the lollies I got distracted. Although I did find an interesting study claiming that Gummi Bears were good for tooth decay.
I suppose that like in 1945, it's better not to succumb to "that lollie curse" and give children any lollies at all, gummy or not. If I do though I'll certainly follow Modern Mothercraft's advice and stay away from "sticky jawy" things. Not only are they terrible for teeth, but you don't see them in shops much anyway. So, that's an easy win for doing what Plunket recommended in 1945!