Pages H1303–H1304: S. T. Ballard, R. H. Nations, and A. E. Taylor. “Microvascular pressure profile of serosal vessels of rat trachea.” Measurements of microvessel diameter were overestimated because of a calibration error. The corrected vessel diameters are 0.56 times those originally reported. The corrected diameter ranges for arterioles, venules, and venular sinuses should be 6–53, 11–42, and 67–236 μm, respectively. When it is assumed that capillaries fall between 10-μm arterioles and venules, capillary pressures predicted by a four-parameter logistical function range from 34.5 and 12.7% of mean arterial pressure. Therefore, when the average large venular pressure was 5% of mean arterial pressure, fractional precapillary (systemic to 10-μm-diam arterioles), capillary (10-μm-diam arterioles to 10-μm-diam venules), and postcapillary (10-μm-diam venules to large venules) resistances would represent 69, 23, and 8%, respectively, of the total microvascular resistance. A revised Fig. 1 comparing experimental data with those of Nordin et al. (3), who measured microvascular pressure in rabbit tracheal mucosa, follows. (See PDF)