Cole's method is employed to measure the internal pressure in body cavity eggs of Rana temporaria. In the interpretation of the results the effect of bending resistance is considered.
The internal pressure in the undeformed egg in isotonic solution, at 25 °C, is 30 dyn/ cm2, corresponding to a stress resultant, or tension, in the vitelline membrane of 1.5 dyn/cm. In hypotonic solutions substantial increases in the pressure have been recorded.
When the pressure is studied as a function of temperature an anomalous high pressure is found at 16 °C for all the different incubation media employed.
A new method is applied to determine Young's modulus of the membrane. The result obtained is 3.7x105 dyn/cm2 at 23 °C.