Not until the mid-1950's (in Japan) did people begin to notice a "strange disease". Victims were diagnosed as having a degeneration of their nervous systems. Numbness occurred in their limbs and lips. Their
speech became slurred, and their vision constricted. Some people had serious brain damage, while others lapsed into unconsciousness or suffered from involuntary movements. Furthermore, some victims were thought to be crazy when they began to uncontrollably shout.
People thought the cats were going insane when they witnessed "suicides" by the cats. Finally, birds were strangely dropping from the sky. in July 1959, researchers from Kumamoto University
concluded that organic mercury (in fish) was the cause of the "Minamata Disease".