ABSTRACT
It is well known that the Arab physician Ibn El Nafees [607 H./1210 A.D.-676 H./1288 A.D,] was the first to discover clearly the lesser or pulmonary circulation between the heart and lungs. What was the historical and anatomical basis of this discovery? Had some trials been made by earlier Arab anatomists to describe the blood circulation in man? .In this paper some light is going to be shed on these problems. The reference used for these previous trials before the age of Ibn El Nafees to describe the blood circulation in man is the encyclopedic work entitled Miracles of Creatures" by Imani Abdu Allah.Zakariya lbn Mohained Al Kazwini [600 H./1204 A.D.-686 H./l283 A.D.]. This book represents an invaluable great encyclopdia containing astronomy, geography. minerals, plants, animals, in addition to some medical studies on the human body including anatomy. In this book some human organs were described in an attempt to study the blood circulation in man by early Arab anatomists. In the following paragraphs the statements of Al Kazwini, reflecting a period before the time of Ibn El Nafees, about certain human organs like heart, liver, arteries and veins are quoted and subjected to comment