The organism isolated conformed to the usual criteria for M. tetragenus. On subculture 4 variant forms of colony appeared (yellow, translucent, pink and brown), each characterized by distinctive biologic reactions as regards sugar fermentation, gelatin liquefaction, pigment production and morphology of the component cocci. There was evidence of constant reversion or transformation of one form into another. One of the variants resembled the staphylococcus in biologic reactions. Hence it is necessary in classifying bacteria to deal with known variant forms.