Naturalist and author, Muir gained the establishment of Yosemite National Park. ALS, one page, 8.5 x 11, February 18, 1908. Letter to Minnesota journalist W. J. Dornuf. In full: “As far as I have seen stimulants & narcotics never give increased sustained strengths of any sort, though useful in sickness.” In fine condition, with intersecting folds, one through a single letter of signature, light mirroring of ink from premature folding, and some mild toning. Pre-certified PSA/DNA and RRAuction COA.