The strain of mouse cells designated NCTC clone 1469 was developed several years ago (5) from a single cell isolated from a culture of the parenchymal liver epithelium of a young mouse of

clone 1469 was developed several years ago (5) from a single cell isolated from a culture of the parenchymal liver epithelium of a young mouse of the C31I-IIeN line (4). The strain grows well in T-60 flasks in a stock medium of 40 per cent horse serum, 920per cent chick embryo extract, and 40 per cent balanced saline (v/v).1 Under these cir cumstances it stones glycogen rapidly in the pres ence of suitable precursors.2 Several years ago its parent cell strain NCTC 7921 was also found to store glycogen in considerable quantity (192). The study reported here was one phase of an attempt to grow the strain in agitated fluid suspension with continuous gassing (1). In part of the study, counts were made at each fluid change and samples of the pertinent fluids taken for analysis. At the end of the experimental period the cells were harvested for study. The adjustment to growth in the shaker flasks was accompanied by certain peculiarities in the growth and metabolism of the strain that are brought out in the text.