White Blood Cells of the Normal Guinea Pig.

Investigators have long since realized the importance of the guinea pig as an experimental animal. A criterion of normality in the blood picture of this animal is a necessity to establish a standard for comparative research. Many studies of the differential count of guinea pig blood have been attempted, but, the variations have been so great that a generalization concerning the average count has been impossible. The cause of these divergences may have been due to the breed of the animal, to the physical condition of the animal, to the morphological criteria used for classification, or to the fact that the experimental series were too small. It is our belief, for reasons to be brought out later, that the animals in certain cases were by no means normal, in other cases the morphological criteria were at fault, and in a particular thesis conclusions were drawn from an experimental series consisting of two animals.

The experiments under investigation suggest that the variability, in percentage cell counts, in a series of over one hundred counts, on 40 guinea pigs, is not as great as the differences in the total cell counts given by various investigators. The greatest differences in these observations occur in lymphocyte and neutrophile distributions, as is shown in the following tabulation of results:

We have calculated statistically the normal distribution of cell types. Our data indicate that the lymphocyte count is between 70 to 80 per cent, the neutrophile between 12 to 18 per cent, and the ecsinophile count between 1 to 2 per cent. We have also calculated the occurrence of Kurloff bodies in the mononuclears and find them to occur in approximately 1.5 per cent of the total cell count, while that type of cell which contains them averages between 5 to 7 per cent of the total cell count.