An Improved Method for the Determination of Hemoglobin in Chicken Blood*

During the past few years considerable interest has been shown in the hemoglobin content of chicken blood, especially in the relation of diet and egg production to changes in this blood constituent. The few hemoglobin values which have been reported for normal chickens of the same breed and age show differences rather large in extent. Holmes and coworkers (1) have discussed recently the variations in some of the values found in the literature. The discrepancies are undoubtedly due partly to the use of methods with different standards and to the difficulty in dealing with blood containing nucleated erythrocytes. It is obvious that the first error can be eliminated only when all workers use a standard method. The latter difficulty, however, prevents the application of the widely used acid hematin methods unless proper modifications can be worked out. The Dare hemoglobinometer was used in our laboratory for the early work with chickens (2). Although we were cognizant af the limitations of the original Dare instrument, we felt that it was accurate enough to detect the large differences between normal and anemic animals. When the Newcomer method was adopted for general use in our laboratory, we applied this method to chicken blood (3). The Newcomer method was never as satisfactory for chicken blood as for mammalian blood because the turbidity of the acid solution makes it difficult to compare the unknown solutions with the standard. Dukes and Schwarte (4) applied a correction factor for at least part of the turbidity encountered in the acid