The Snail's Foot as a Langmuir Trough

Abstract

THE importance of the surface film of protein on stationary or slowly moving bodies of water as a food for small aquatic animals had apparently not been realized until the recent work of Goldacre¹, who made film-pressure measurements on ponds, lakes and rivers and found on all of them unimolecular layers of protein in higher or lower states of compression. A concomitant study of the behaviour of small aquatic animals led him to the conclusion that they ate this protein in large amounts. Observations of the movements of dust particles in a film during its ingurgitation by a tadpole indicated that this animal might well eat its own dry weight of protein, spread as a monolayer at the air–water interface, in one day.