Comparison of calculated chain order in a membrane with the deuteron magnetic resonance data. Order parameter at 28 C is shown as a function of a position along the chain. ---- calculation for different values of lateral pressure (in dynes/cm); ___ data by Seelig and Niederberger. The results indicated the existence of lateral pressure in bilayer and biological membranes. The integral value of pressure is of the order of 25 dynes/cm. This value remains unchanged today, but the full pressure profile is known from more recent work by Gruen and by Ben-Shaul and collaborators. From: S Marcelja, Chain Ordering in Liquid Crystals II. Structure of bilayer membranes Biochimica et Biophysica Acta, 367 (1974) 165-176