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Abstract

This experiment was undertaken under the direction of Dr. A. C. Ivy to ascertain the quantity of blood which, when taken by mouth, will produce a tarry stool.

Ten healthy medical students were the subjects of the experiment. The procedure employed was essentially the drinking of venous blood drawn from the subject and subsequent gross examination for a tarry stool; that is, a stool which was black and glistening. No microscopic or chemical tests for blood were used, for the results of such an examination are not obtained in a patient's history. Progressively larger quantities of blood were taken by the subject until a tarry stool occurred. Sufficient time in each case was allowed for passage of the blood through the gastrointestinal tract before larger quantities were taken. Each subject was allowed to eat a general diet of his own choice; in addition, four of the students repeated the experiment