1. Statistical analyses have been made of the weekly variations in the blood counts of groups of normal rabbits to find whether there exists any relationship between the numerical changes occurring in the various cell types.
Consecutive blood counts and differential white cell determinations on five groups of normal male rabbits comprising 45 animals in all were made at weekly intervals from October, 1927, to June, 1929, the number of observations on each group varying from eight to thirty-five.
2. The following relationships between the varying group means were found to be consistent and significant:—The number of the red blood cells varied with the amount of hemoglobin per cubic millimeter and with the number of lymphocytes. There was an inverse relationship between the amount of hemoglobin and the number of monocytes. The neutrophiles varied in number with the monocytes; the basophiles with the eosinophiles; and the eosinophiles with the monocytes.
Other associations not always similar but of high significance as far as the combined values were concerned, were the relations of the red blood cells with the basophiles and the monocytes. The relations of the neutrophiles with the red blood cells and the hemoglobin were very irregular.
3. Significant association of the white blood cells with variations in the red blood cells and the hemoglobin content were observed. The numerical variations in the group means of the total white cells were associated with similar variations in the group means of the neutrophiles, the lymphocytes, the monocytes, the basophiles, and the eosinophiles almost to the degree of their numerical occurrence in the peripheral blood.
4. With the exception of the total white cells, approximately only half the variations in the group levels of the various cells and of the hemoglobin content can be accounted for on the basis of simultaneous associations with each other.
5. The red blood cells, the lymphocytes, and the basophiles as one group, the eosinophiles and the monocytes as another group, and the hemoglobin content and the neutrophiles as a third group, described a definite shift from a high to a low numerical value during the 2 year observation period. From the standpoint of the magnitude of the shift, the basophiles, the eosinophiles, the monocytes, the lymphocytes, and the red blood cells participated in the order mentioned. The neutrophiles were only slightly affected and the hemoglobin content relatively not at all.
6. No significant relationship was ever found, even in the component groups, between the weekly mean values of the following: the hemoglobin with the basophiles, the eosinophiles, or the lymphocytes; the neutrophiles with the basophiles or the eosinophiles; and the lymphocytes with the eosinophiles or the monocytes.