blood

A liquid which, in man and all the higher animals, circulates through the system, being propelled into the arteries by the heart and received back by that organ through the veins. Histologically considered, b. is a ti ue, with solid or semisolid cellular elements and a liquid intercellular substance. In mammalian b., the cellular elements are red blood corpuscles, white blood corpuscles, and. the blood plates.^ Chemically considered, b. consists principally of proteins, sugar, lecithin, cholesterin, fat, fatty acids, carbonic acid, hydrochloric acid, and phosphoric acid, as well as the inorganic bases, sodium, pota ium, and magnesium in combination with one of the above mentioned acids. Ammonium carbonate, urea, uric acid, amino-acids, and other compounds have been found in normal blood. When drawn from the b. ve els, b. tends to form a semisolid ma (clot, coagulum). It consists of a clear liquid, called plasma, in which the corpuscular elements are suspended, arterial b. 1. The bright red or scarlet b. normally contained in the left cavities of the heart, the systemic arteries, and the pulmonary veins, also the umbilical vein of the fetus. It contains a relatively large amount of oxygen and a small amount of carbon dioxid. 2. The blood contained in the arteries without regard to its qualities, b. agar. Agar mixed with sterile b. and used as a favorable culture medium for such bacteria as the gonococcus and pnemno coccus.