Abstract
We use light scattering and conductimetry to investigate the very dilute range of the domain of existence of the sponge (L3) phase in the quaternary OBS/pentanol/brine system. In this part of the phase diagram we find a line of maximum turbidity where the scattered intensity shows a very sharp maximum and has a pure Ornstein Zernicke q-dependence. These features are not consistent with what is expected close to the symmetric asymmetric transition line. We question the possibility of the spontaneous tearing of the membrane first considered on theoretical grounds by Huse and Leibler ($Phys.~Rev.~Lett.$ 66 (1991) 437).