Quinton reported in 1897 that he had replaced the entire blood volume of a dog with sterilized isotonic seawater and that the animal recovered within five days and survived for five years. The experiment was presented as the empirical foundation for the Law of Marine Constancy and for the claim that isotonic seawater is biologically equivalent to blood plasma.

Skeptical physician Harriet Hall commented on this report: “Extraordinary claims require extraordinary evidence, and this century-old report doesn’t even meet the standards of ordinary peer-reviewed published evidence” (Wikipedia, René Quinton, accessed 2026-06-27). The experiment has not been replicated under controlled conditions in modern biomedical literature. The survival of the dog, if accurately reported, could reflect the partial electrolyte-replacement function of isotonic saline rather than any unique “marine milieu” property, since similar experiments with pharmaceutical saline have produced variable outcomes depending on the volume and rate of replacement. The animal endpoint here is a surrogate for the proposed human clinical application; no human equivalent of complete blood replacement with seawater has been documented.