The quality of mercy is always strained, but snake oil comes raw and unfiltered, harvested from ever more lethal snakes. You might think the accounts of the suffering of those stricken with the Ebola virus would soften the hearts of snake-oil salesmen. But the more horrific the suffering, the more inspired the sales pitches. The con men are flooding the Internet and some homeopathic health stores with tonics and elixirs that boast of miraculous powers to prevent or cure sickness from the Ebola virus. The grim fact is that there is neither a preventative nor a cure. Josephine P. Briggs,...