Soon afterwards Chabry, in discussing the embryology of the Ascidians, indicated many of the points in which the contacts between cells repeat the surface-tension phenomena of the soap-bubble, and came to the conclusion that part, at least, of the embryological phenomena were purely physical12; and the same line of inôÙvesôÙtiôÙgaôÙtion and thought were pursued and developed by Robert, in connection with the embryology of the Mollusca13. Driesch again, in a series of papers, continued to draw attention to the presence of capillary phenomena in the segmenting cells {307} of various embryos, and came to the conclusion that the mode of segmentation was of little importance as regards the final result14.
Lastly de Wildeman15, in a somewhat wider, but also vaguer generalisation than Erreraãs, declared that ãThe form of the cellular framework of vegetables, and also of animals, in its essential features, depends upon the forces of molecular physics.ã
Let us return to our problem of the arrangement of partition films. When we have three bubbles in contact, instead of two as in the case already considered, the phenomenon is strictly analogous to our former case. The three bubbles will be separated by three partition surfaces, whose curvature will depend upon the relative
size of the spheres, and which will be plane if the latter are all of the same dimensions; but whether plane or curved, the three partitions will meet one another at an angle of 120ô¯, in an axial line. Various pretty geometrical corollaries accompany this arrangement. For instance, if Fig. 114 represent the three associated bubbles in a plane drawn through their centres, c, cÿ£¢ãý, cÿ£¢ã° (or what is the same thing, if it represent the base of three bubbles resting on a plane), then the lines uc, ucÿ£¢ã°, or sc, scÿ£¢ãý, etc., drawn to the {308} centres from the points of intersection of the circular arcs, will always enclose an angle of 60ô¯. Again (Fig. 115), if we make the angle cÿ£¢ã°uf equal to 60ô¯, and produce uf to meet ccÿ£¢ã° in f, f will be the centre of the circular arc which constitutes the partition Ou; and further, the three points f, g, h, successively determined in this