On the Physiology of Amoeboid Movement

CONTINUOUS amoeboid movement is essentially a rhythmic phenomenon (Pantin, 1924), to some extent comparable with rhythmic contraction in muscle. Yet no complete investigation of the action of ions has been made which enables this unspecialised contractile mechanism to be compared with heart-muscle and cilia. The subject is important because in unicellular organisms the state of the cell can be observed simultaneously with the movement; it can also be seen at once if all the cells react in the same way. In muscle only indirect evidence can be obtained on these points. Marine amoebae are peculiarly suitable for this work, because the composition of sea-water is accurately known and an artificial medium therefore prepared with comparative ease. Quantitative results are obtained by selecting a species of the litnax type and measuring the rate of movement.