Blood Counts in Experimental Poliomyelitis in the Monkey

Blood counts were made on six series of monkeys before and at various intervals after the injection of active poliomyelitic virus. From the data thus obtained the variations in the circulating white cells have been followed in the several stages of the disease (a) before injection, (b) during the incubation period, (c) during the acute stage, including the stage of prostration, and (d) during recovery. On account of experimental conditions not all the monkeys were observed during the four periods, so that averages of counts in several monkeys are used for comparison. Averages of 121 counts on 40 normal monkeys are recorded. Immediately following the injection of the virus the relative and actual numbers of lymphocytes are slightly diminished. In many cases the curve continues sharply downward. In others from the 4th to the 6th day there is an actual increase for a brief period to a point somewhat in excess of the original count. With the onset of symptoms a lymphocytic crisis takes place. The curve then continues slightly downward, while the polymorphonuclear neutrophilic leucocytes are relatively and actually increased at approximately the same time. During the stage of prostration the curve of the polymorphonuclear neutrophilic leucocytes returns to almost normal, while the lymphocytic curve continues slightly downward. With recovery the lymphocytes slowly return to normal after several weeks. There is no evidence of lymphocytic stimulation after recovery. Eosinophilic, basophilic, large mononuclear, and transitional leucocytes follow the depressions and stimulations exhibited by the neutrophilic cells of the same series. The results here recorded are consistent with the observations of Peabody, Draper, and Dochez on human cases. The increase in the total number of circulating lymphocytes after the lymphocytic crisis is coincident with the passing of the acute stage. Additional evidence is presented to indicate that Smillie produced atypical but definite poliomyelitis in the monkey with cultivated virus.