Recherches experimentales sur le mouvement des liquides
dans les tubes de tres petits diametres. Mem. Acad. Roy. Sci. (Paris), 1846, 9, 433-544
More than a century after Hales, Jean-Leonard-Marie Poiseuille, a French physician and physicist, was the first to make an important contribution to the physiology of circulation. In 1828, he invented a mercury manometer (haemodynamometer) that he used to repeat Hales' experiments on blood pressure. The haemodynamometer was a glass U-tube filled with mercury connected to a cannula which was inserted into an artery. Poiseuille used potassium carbonate and then sodium bicarbonate ("sous-carbonate de soude") as an anticoagulant in his experimental work. This new instrument was a great advance compared to the long tube used by Hales.
During his experiments in animals, Poiseuille observed that the blood pressure rises on expiration and falls on inspiration. In his work, Poiseuille wrote: "...Il est inutile de dire que l'abaissement du mercure correspond a l'inspiration, son elevation a l'expiration. Ce sera donc en prenant la moyenne entre les deux colonnes de mercure qu'on obtiendra veritablement celle due a la force du coeur."
He performed these measurements of the blood pressure at the level of the aorta, carotid, brachial, axillary and femoral arteries. His findings led him to conclude that "a molecule of blood moves with the same force within the entire arterial system." Poiseuille also measured the degree of arterial dilatation after each cardiac contraction during these investigations.
Poiseuille's hemodynamometer had very limited applications in clinical practice. Jean Faivre was the first to use this instrument to measure blood pressure in man. He performed this study in a patient who underwent amputation of a limb and obtained a systolic pressure of 120 mm mercury.
Despite its limited clinical applicability, Poiseuille's discovery was a major step forward and laid the foundation for clinical physiology.
Poiseuille also investigated the flow of liquids in small tubes which was extremely important in the study of blood viscosimetry (Poiseuille's Law).
Faivre J. Etudes experimentales sur les lesions organiques du coeur. Ann Soc Med Lyon 1856; 2 ser,4:180-88