1. Introduction
Blood is a circulating connective tissue of vertebrates containing
plasma (albumin, globins, mineral salts, and other solutes in
water) and cellular or formed elements (erythrocytes or red blood
cells, RBCs; leucocytes or white blood cells, WBCs; thrombocytes).
In mammals, instead of thrombocytes, blood has platelets (PLTs),
that are not full cells but very small fragments of bone marrow’s
megacaryocytes. Moreover, when mature, mammalian RBCs are
anucleate, so whether or not these (nucleous-lacking) corpuscles
should be considered cells is still under debate. On the other hand,
the microscopic identification of blood needs the presence of any