Editing On Growth and Form (section)

===7. The Forms of Tissues, or Cell-aggregates===

(1st p. 293 – 2nd p. 465 – Bonner p. 88)
::Thompson observes that in multicellular organisms, cells influence each other's shapes with [[triangle of forces|triangles of forces]]. He analyses [[parenchyma]] and the cells in a [[embryogenesis|frog's egg]] as soap films, and considers the [[symmetry|symmetries]] bubbles meeting at points and edges. He compares the shapes of living and fossil [[corals]] such as ''[[Cyathophyllum]]'' and  ''[[Comoseris]]'', and the hexagonal structure of [[honeycomb]], to such soap bubble structures.