Imbibition in Disintegration.

Abstract

Studies of the lethal effects of cyanide solutions on Amblystoma punctatum embryos have demonstrated that water relations play an important rôle in their subsequent disintegration. The manner in which this water is taken up, whether by osmosis or imbibition, has received little attention. The separate evaluation of water in these 2 rôles appears essential to a basic understanding of the disintegration process.

Measurements of density should help to reveal the nature of the water entering the tissue for it is generally recognized that water of imbibition increases in density whereas water taken up osmotic-ally does not increase in weight per unit volume. An embryo imbibing water will increase its weight when weighed in water and will at the same time decrease the total volume of embryo plus solution. An embryo taking up water by osmosis, however, may increase its own volume but the total volume of the embryo and solution will remain constant. Water taken up in this manner will not alter the weight of the embryo when weighed in water. To determine the amount and rate at which Amblystoma punctatum embryos took up water by imbibition, the following method was used:

A small Gooch crucible was suspended by a fine wire from one of the hooks of an analytical balance. A beaker containing the cyanide solution (M/125,000 in tap water) was placed beneath the crucible so that it hung completely immersed in the solution. Weights were hung from the hook above the crucible to balance the pan on the side opposite.

The embryos used were in the yolk plug stage enclosed only in the vitelline membrane. Twenty-five were introduced into the crucible in each trial. The weight of the embryos was then recorded as quickly as possible and at intervals of one-half hour thereafter until disintegration began.