ABSTRACT
Blood is composed of the liquid plasma and the blood cells. While many workers include the chemistry of plasma as a part of hematology. The chapter reviews the limits of the "toxicophysiology" of blood cells only. The blood cells of teleost fish are produced in the hematopoietic tissue which is located primarily in the spleen and kidney. The erythrocytes (red blood cells) of fish are nucleated and similar in size to the leukocytes, in contrast to mammals in which the latter are the much larger cell. Fish erythrocytes are easier to count than mammalian ones because they are larger and fewer in number. Cadmium also causes an abnormally large number of malformed erythrocyteset which implies a lesion in the machinery for forming blood cells. Chronic exposure of the cyprinid Barbus to lead for up to 60 days at 47 µg/L resulted in severe reductions in erythrocyte count, hematocrit, hemoglobin concentration, and Mean corpuscular volume (MCV).
