> "Seeking the Magic Mushroom" is a 1957 photo essay by amateur mycologist Robert Gordon Wasson describing his experience taking psilocybin mushrooms in 1955 during a Mazatec ritual in Oaxaca, Mexico.
https://en.wikipedia.org/wiki/Seeking_the_Magic_Mushroom
I found this issue of Life in the Internet Archive, here's the Magic Mushroom photo essay: https://archive.org/details/sim_life_1957-05-13_42_19/page/1....
The KKK baseball team story is a report, not an advertisement (although there's an insane amount of ads in that magazine): https://archive.org/details/sim_life_1957-05-13_42_19/page/4....