Betrachtung an einer fluiden Grenzfläche

A theory of the elasticity of lipid bilayers is proposed. Three types of strain, i. e. stretching, tilt and curvature, are distinguished and the associated stresses are identified. It is argued that in the case of vesicles (= closed bilayer films) the only elasticity controlling nonspherical shapes is that of curvature. Euler-Lagrange equations are derived for the shape in magnetic fields and under excess outside pressure. It is shown that magnetic fields can deform spherical vesicles into ellipsoids of revolution. Under excess outside pressure the spherical shape becomes unstable at a certain threshold pressure. Both effects can be influenced by a spontaneous curvature of the bilayer. Some possible experiments to determine the elastic properties are also discussed

We have examined the blood of man and of the rabbit, dog, guinea pig, sheep, and goat. There exists a great difference in the size of the red blood cells of these animals, but the total surfaces of the chromocytes See PDF for Structure from 0.1 cc. blood do not show a similarly great divergence, because animals having very small cells (goat and sheep) have much greater quantities of these cells in their blood than animals with blood cells of larger dimensions (dog and rabbit). We give all the results of our experiments, omitting only those in which we were unable to avoid losses in the procedure of evaporation of the acetone. It is clear that all our results fit in well with the supposition that the chromocytes are covered by a layer of fatty substances that is two molecules thick.