Abstract
The treatment of the problem which was given in previous publications is generalized so as to include not only the part played by the changes of the surface tension, but also that played by osmotic forces. Whenever any reactions take place in a liquid drop of the kind considered previously, there is always a difference of concentrations inside and outside of the drop. The forces caused by this difference are such that they always tend to divide the drop. The surface tension counteracts this tendency. As a result of this, the drop will divide only above a critical size. Calculations of this critical size leads to dimensions of actual living cells.