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August 18, 1945


JAMA. 1945;128(16):1167-1168. doi:10.1001/jama.1945.02860330035013

In 1912 Bass and Johns1 reported a method for the cultivation of two species of malarial parasites of man. Blood drawn from a malarial patient was expelled directly into a defibrinating tube containing 0.1 cc. of a 50 per cent dextrose solution for each 10 cc. of blood taken. Defibrination was effected by gentle stirring with a glass rod. The defibrinated blood was allowed to sediment at incubator temperature (40 C.) until a column of serum 1/2 to 1 inch deep was above the sedimented cells. The parasites live and develop in the half millimeter top layer of the sedimented cells. All parasites beneath this top layer die and disintegrate. In such a culture the young parasites increase in size during the first twenty-four hours. Segmentation begins in about thirty-six hours. Extracellular parasites are rapidly ingested and destroyed by leukocytes. A free asexual malarial parasite cannot live longer than a few minutes in normal human serum. Probably, therefore, malarial plasmodia can pass from cell to cell only when the cells are in direct contact.