The study of blood cells with the electron microscope necessitates special methods which as yet are not completely precise. The methods of smearing on Formvar, of destruction by pressing on a wet smear, and of shadow casting are those which have been used most frequently.
The author reviews the electron microscopy of thrombocytes, granulocytes and erythrocytes and discusses the ultrastructure of the hyaloplasm. Azurophilic, neutrophilic and eosinophilic granules can be very well observed with the electron microscope. Chronic and acute luekemic cells exhibit certain granules and paracrystals, the significance and specificity of which are not yet clearly established.