“…Estabrook (12) described the application of fluorimetric techniques for the measurement of metabolic intermediates. The adaptability of the technique is demonstrated by the variety of situations to which it has been applied, e.g., resting cell suspensions (1, 6), whole intact organs (10), and individual mammalian cells (18). Fluorimetry has recently been used to follow nicotinamide nucleotide reduction in growing bacterial cultures by means of a flow cell (23).…”