A simple motorized device to facilitate the spreading of inocula over agar plate surfaces.

The requirement of large numbers of lactobacillus counts, which are done by spreading aliquots of saliva-glucose broth mixtures with sterile bent glass rods over the surfaces of tomato juice peptone agar (pH 5.0) plates, led to the development of a simple, inexpensive motorized device to facilitate this process. Comprised of a conventional three speed phonograph motor and turntable, the instrument was adapted from the rotor described by Thompson (J. Bact., 36, 539, 1933), of which a modification with a footswitch was at one time commercially available. An aluminum petri dish cover (Brewer, J. Bact, 59, 237, 1950) was centered and fastened to the turntable after some of the adsorbent pads for the cover were cut to mask the center post. Then more