Well, didn't Laura Ingalls Wilder's sister lose her sight to Scarlet Fever? Couldn't that have been it?

It could have been, but in Mac's case, they were still worried about his vision after he recovered from the fever, whereas for Mary, the damage was done while she was sick.

Also, he first got sick when he was about seven, which I think would most likely rule out syphilis.

Children can get syphilis from their parents (at birth), right?

Yes, and can get it from breastmilk if they are wet-nursed. (Which nobody is today, but was very common in previous centuries.)

Mary lost her eyesight due to damage from rheumatic fever caused by scarlet fever. Mac had scarlet fever originally, but I never understood the idea that he had to not use his eyes or he'd be blind, except as a novelistic device. It's possible people thought that.

Before the Industrial Revolution, tuberculosis may sometimes have been regarded as vampirism. When one member of a family died from it, the other members that were infected would lose their health slowly. People believed that this was caused by the original victim draining the life from the other family members.

Yep! Mercy Brown, the Rhode Island vampire! [link]

Didn't one of the Five Little Peppers have to not use her eyes or she'd go blind?

t back to Wikipedia

((is having a really hard time repressing the "or you'll go blind" jokes))

((is having a really hard time repressing the "or you'll go blind" jokes))

OMG, Polly Pepper SO would not do that! Mary Ingalls on the other hand...

Herbert died. Elsie feels guilty, but her father says that any blame should be on him, not her. He also says,

And even if I had allowed you to decide the matter for yourself, you would have done what was your duty in refusing to promise to belong to one whom you love less than you love your father.

Oooh! Oooh! Mr. Dinsmore has an eccentric elderly old-maid aunt, and Elsie is going to go visit her in Ohio!