The New International Encyclopædia/Micellar Theory

MICEL′LAR THEORY (from Neo-Lat. micella, diminutive of Lat. mica, crumb). A theory proposed by the botanist Nägeli in 1862 to account for the physical properties of organized bodies like starch grains, cell walls, etc. He assumed that the molecules of the chemist are united into larger unions, constituting molecules of a higher order, which he called micellæ. These hypothetical micellæ are extremely minute, never being visible even with the highest powers of the microscope. He further claims that the growth in thickness of a cell wall is due to the intercalation (intussusception) of new micellæ of cellulose between the micellæ which have become widely separated from each other by the stretching of the wall. Strasburger, the most important opponent of the micellar theory, holds that the growth in thickness of a cell wall is due to the deposition of material upon its inner surface. The micellar theory is still current, but is not so strongly supported as formerly.