(4) The Cause of the Disease and Governmental Opinion

1.Establishment of Chisso Co., Ltd. and Outbreak of Minamata Disease

Parallel to the consultation and medical examination on ordinary invalids, the Medical Study Group made clinical observations of patients in the hospital affiliated to the Kumamoto University Medical School. They also made autopsies on deceased bodies and analyzed the drinking water, sea water, soil and marine products sampled in the bay, employing microbiology, hygienics, and public sanitation. They also made autopsies on deceased bodies and analyzed the drinking water, sea water, soil and marine products sampled in the bay, employing microbiology, hygienics, and public sanitation.
The Medical Study Group has proposed the theory on the causal substance of Minamata Disease known as "organic mercury theory" , saying "mercury is suspected as the most likely substance responsible for seafood contamination. The Medical Study Group has proposed the theory on the causal substance of Minamata Disease known as "organic mercury theory" , saying "mercury is suspected as the most likely substance responsible for seafood contamination. Chisso has then announced "the company's opinion against the organic mercury theory" in response to the above, thereby Meanwhile, various etiological hypotheses such as "explosive theory" and "amine theory" were found to be "inadequate" and "inadequate". Meanwhile, various etiological hypotheses such as "explosive theory" and "amine theory" were proposed.
In 1962, the Medical Study Group reported that organic mercury crystals were detected in the sludge discharged from Chisso. Damages have been multiplied by such delay in response. Damages have been multiplied by such delay in response.
In September 1968, the national government issued "the governmental views on Minamata Disease" based on the latest In September 1968 the national government issued "the governmental views on Minamata Disease" based on the latest knowledge and information obtained thereby supporting the explanation that Minamata Disease is a toxic symptom of the central nervous system due to the acetaldehyde manufacturing process of Chisso Co. The "Minamata Disease" based on the latest knowledge and information obtained thereby supporting the explanation that Minamata Disease is a toxic symptom of the central nervous system due to methylmercury compound, which is discharged from the acetaldehyde manufacturing process of Chisso Co. They declared that Minamata Disease is caused by a large consumption of seafood in which methylmercury compound is discharged from the acetaldehyde manufacturing process of Chisso Co. Since then, Minamata Disease and Niigata-Minamata Disease have been officially designated as "a pollution Since then, Minamata Disease and Niigata-Minamata Disease have been officially designated as "a pollution-related disease".