Bob Friedel wrote: > McFarland Standards are composed of Barium Sulfate suspensions (scale 1-10). > You will also need a Wickerham card to compare the McFarland standard with > the organism suspension. See Difco Manual 10th edition, p. 565, 1984. > > They can be purchased for $5.45 each from Hardy Diagnostics Also from BioMerieux Loes