Differentiation of Avian Thrombocytes from Leukocytes by Use of Giemsa’s Stain

Abstract In the course of investigation of the leukocytic response to artificial infections with Eimeria tenella in chickens, considerable difficulty was encountered in the differentiation of thrombocytes from small lymphocytes. Initially blood films for differential counting were prepared in the conventional manner and stained by Wright's Method, as described by Lucas and Jamroz (1961). In the microscopic examination of films stained by this method, monocytes, large lymphocytes, and polymorphonuclear cells were easily distinguished. However, thrombocytes and small lymphocytes were often confused, in spite of close adherence to the diagnostic criteria for these cells as set forth by Lucas and Jamroz (1961). In view of the unsatisfactory results with Wright's stain, an alternate method was sought. The high degree of cellular differentiation reported for Giemsa's stain when used for blood parasites led to the investigation of the use of this method as a routine blood film-staining procedure. Blood films were prepared within . . .