Variation patterns in the respiration of avian embryos.

Our own data and those in the literature show that the increase in body weight and respiration rate in avian embryos is divided into three periods. Equations are given that describe the increase in weight and oxygen-consumption rate during individual periods and throughout embryogenesis. The meaning of the coefficients in the equation relating body weight to respiration rate is clarified. It is hypothesized that the analytic expression representing respiration rate as a function of embryo weight can aid in finding relationships between respiration and other parameters of the developing organism.