At the Baltimore meeting of the American Institute of Homoeopathy, where the use of rosin-weed in hay fever was first reported, Dr. John Sutherland, of Boston, made the proper criticism that if rosin-weed was harmless and could not produce any effect on the healthy body, he could not understand how it had any power to cure. To this, I had no answer except that I had both taken and given large doses for many years to patients of all ages and had never seen any symptoms develop. Another speaker suggested that, like calcarea and silica, potentization would develop pathogenetic powers that were not evident in the crude drug. This I have never tried. As related in the chapter on Bacterial Vaccines, I suspect that the curative power of rosin-weed in hay fever lies in its power of relieving a coexisting catarrh, of which theory we have the confirming evidence that other methods that cure catarrh, nasal operations, bacterial vaccines, homoeopathic remedies, have often cured a coexisting hay fever. Since that discussion, I have found Dr. Hall's proving. It would be a pleasure to find that our old family remedy for hay fever really acts on the homoeopathic principle but I believe that the question needs the verification of further proving. Transcriber's Notes: Footnotes have been placed at the end of chapters. Obvious punctuation errors repaired. All oe ligatures have been replaced with "oe" (eg: "homoeopathic") page 52 "posioning" changed to "poisoning" (uric acid poisoning) page 57 "familes" changed to "families" (gouty familes are especially) page 69 "urid" changed to "uric" (so-called uric-acid disorders) page 95 "Immutiny" changed to "Immunity" (Passive Immunity) page 97 "Inthe" changed to "In the" (In the Centralblatt für) End of the Project Gutenberg EBook of The Treatment of Hay Fever, by George Frederick Laidlaw