When pea embryos are placed in water solutes leak from them at a rate which declines rapidly at first and then more slowly. Embryos can be dried down over calcium chloride and will then leak as before when returned to water. Similar results were obtained with Ricinus seeds after removal of the testa. Pea embryos that have first been allowed to imbibe some water through a small part of their surface (by placing them on damp filter-paper) leak relatively slowly when subsequently immersed in water; the greater the initial imbibition the slower the subsequent leakage. Likewise, embryos taken from peas that were harvested when succulent and tender show only slow leakage It is proposed that as seeds dry out in the course of development cell membranes lose their integrity. When such dry seeds are allowed to imbibe water there is a short period, before membrane integrity is re-established, during which solutes can leak out of the cells.