Herrmann von Helmholtz on the cure of hayfever

It was difficult to find but I knew it should be there: a letter of Herrmann von Helmholtz about his private attempt to cure hay fever. Published in the increasingly important Nature magazine on May 14, 1874 von Helmholtz describes the vibrio like bodies in his own nasal fluid and the successful local treatment with quinine.

Unfortunately there is a consecutive letter that did not confirm this effect. I also do not know how this treatment would have worked. Fiction, placebo or true antiparasitic side-effect? We even know of quinine induced allergy, making even reverse causation possible.

G. Kanny, J. Flabbée, M. Morisset M, D. Moneret Vautrin. Allergy to quinine and tonic water. Eur J Intern Med 14 (2003), p. 395-396.
R. Cundall, Idiosyncrasy to quinine in bitter lemon. Br Med J 20 (1964), p. 1638.