CAUSES OF VARIATION IN THE PLATELET COUNT: EXPERIMENTAL RESULTS SHOWING THE EFFECT OF DIPHTHERIA TOXIN, BENZOL AND TUBERCULIN ON THE PLATELET COUNT IN RABBITS

Prior to the introduction of the Wright and Kinnicutt method,1 the technic for counting blood-platelets was either so laborious or so inexact that very little interest was taken in the subject by clinicians, and very few results were reported. The results reported have been at variance. Investigators have not agreed on the platelet count in health, nor on the changes which occur as a result of disease. The divergent opinions regarding the normal count are due evidently not only to the use of different counting methods, but also to a lack of unity regarding the identity of platelets. Differences of opinion respecting the pathologic changes in the count are largely due, as I shall endeavor to point out, to the fact that the count may be enormously increased or decreased by the action of the same agents. It would appear that in some diseases very high and very low counts