There are case studies based on historical realities and there are scientific reports on this altogether different metal called Mercury that stays in liquid form on room temperature. The hazards it can cause are much more severe and serious than one can imagine and anticipate. David Hammond, in his book Mercury Poisoning: The Undiagnosed Epidemic has done a phenomenal job by enlightening the hidden facts about Mercury which by large are unknown to masses. The book explains the various symptoms caused by hazardous Mercury on health with their side effects and the treatments required to overcome these impacts.
How many of us know that one of the constituents of vaccines is thimerosal which substantially contains mercury. As mentioned in the book Mercury Poisoning: The Undiagnosed Epidemic by David Hammond , Mercury is one of the major factor for causing and increasing autism. But probably there is no alternative for vaccines and hence it cannot be avoided. That is why in such cases David has created the awareness and has left the choice open since there is logically no reason in telling to avoid vaccines. Similarly in case of dental amalgams, there also we have a considerable amount of mercury though there are certain agencies like the American Dental Association that claims it not to carry any volume of mercury. But since here there is a choice to avoid dental amalgams, David clearly prefers readers to go for the alternative for dental fillings.
Overall Mercury Poisoning: The Undiagnosed Epidemic by David Hammond is an interesting and enlightening read for all to learn a lot that is factual but is not known to us.