Well, as I said, things were different back then...

Mostly we used iodine tablets, usually military surplus versions of Potable Aqua- when we used anything. At least one guy ("crazy Chester") refused to drink water unless it had been mixed with grain alcohol for hours.

To be honest... and I'm NOT recommending this... until the late '70s or so, we pretty much drank straight from springs anytime, and from streams if we were certain that there were no camps or houses upstream. I wouldn't do it now, but I never got sick, nor did any of the people I was with. We only used the iodine tablets when there was doubt about the source. Hadn't even heard of giardia at that point, and there were large sections of wilderness that had no other people at all, not even hikers, all year round.

Camping was more unusual then than it is nownow, and it was a little looked-down-upon as something done by people too poor to even afford motels. Backpacking was very unusual until 1968 or so, and grew fairly slowly from then. Everything was a lot less crowded.

These days I carry a Katadyn filter and iodine as a backup. Boiling takes up time and fuel, and that interferes with making progress down the trail. I almost never make open fires, because of the fire scars, and the difficulty of being absolutely sure it's out and won't spread, and the night blindness, and advertising the campsite to anyone for miles around, and...