In the diagnosis and study of the various allergic states it is frequently desirable to know the blood picture, especially the eosinophil count. The ordinary smear method, in which 200 or more cells are counted, is a time-consuming process and the chance for an error in the eosinophil count is great. Moreover, the result gives only the percentage of eosinophils in the number of cells counted. The method described here gives the number of eosinophils per unit volume of blood, is rapid and at the same time gives the leukocyte count.
Blood is collected in the usual manner for the blood count, accurately calibrated white cell pipets being used. In place of the usual acetic acid diluting fluid the following fluid, which is the modification of Camara and Alvarez1 of that described by von Domarus,2 is employed:
The count is made in the usual manner in the ordinary