Duncan MacDougall, a physician in Haverhill, Massachusetts, conducted scientific experiments in proving the existence of the human soul. His theory was to weight a person at the point of death that any lost of mass would show the spirit leaving the body. In 1901, he sought volunteers terminal ill with tuberculosis to participate. In the first experiment, the patient within hours of their death. was placed unto a bed scale, built by Duncan himself, with sensitive springs so percise in weight to exact gram. When the person had passed away, the observed loss of weight was 21 grams. Over the years, he repeated the experiment with other patients and recorded an average lost 21 grams. In 1907, his story published in Journal of American Society for Psychial Research and later circulated by the New York Times.
Duncan could no longer find volunteers for these experiments but continued on with using animals. This was with sheep, mice and the most noted the five dogs which resulted in no sufficient weight lost. The doctor had concluded that dogs possessed no soul. The results of Duncan MacDougall’s experiments remains in debate to this very day. Criticism that his methodology was flaw, his results were inconclusive or false involving the patients and animals, or his reasearch was unscientific. One fact which remains true is this type of experimentation has not been repeated.
Sources of information
Kruszelnicki, Karl. Great Mythconceptions: The Science Behind the Myths. USA. Andrew McMell Publishing. 2006
Pigliucci, Massimo. “Does the soul weight 21 grams?” Rationally Speaking. December 10, 2013. http://rationallyspeaking.blogspot.ca