When to see a doctor. See a doctor if you or a loved one has memory problems or other dementia symptoms. Some treatable medical conditions can cause dementia symptoms, so it's important to determine the underlying cause.
A brief history of tobacco. (CNN) -- Tobacco was first used by the peoples of the pre-Columbian Americas. Native Americans apparently cultivated the plant and smoked it in pipes for medicinal and ceremonial purposes.
1st Generation Pesticides: 1  2500 BC- farmers began using the toxic chemical sulfur to kill off pests from their crops. 2  15th century AD -a variety of chemicals such as, arsenic, hydrogen cyanide, mercury and lead were put to use. 17th century -nicotine sulfate, derived from tobacco leaves was discovered as an effective pesticide and ants were controlled with mixtures of honey and arsenic.