Abstract
A simple method is described for obtaining relatively pure fields of leucocytes from peripheral blood for electron microscopic study. The procedure does not require any unusual skill or equipment and exposes the cells to a minimum of handling before they are fixed. The basis of the method is that glutaraldehyde causes plasma to solidify into a firm substance that can be cut into small pieces and handled as blocks of tissue. By fixing centrifuged blood
in situ, this phenomenon is used to circumvent the difficulty of recovering the usual thin buffy coat with a pipette without also picking up a large number of erythrocytes. The use of glutaraldehyde offers the additional advantages of good preservation and the opportunity to store the specimen in fixative for an indefinite period of time until a convenient time for further processing.
