The Relation between the Form of the Living Cell and the Nuclear Phases of Division in Amoeba proteus (Leidy)

D ESPITE the fact that Amoeba proteus (Leidy) is one of the most widely studied of the non-pathogenic Protozoa, the process of division in this form has not been given the attention that one would expect. There is consequently a dearth of reliable accounts of this process and a conflict in the descriptions of the typical mode of vegetative reproduction. Awerinzew (1904) described division in a form which he identified as proteus but, as it had an ovoid nucleus, it cannot be this but is possibly Amoeba dubia (Sch.). Doflein (1918) gives a clear description of nuclear division but, as we shall point out later, apparently confused resting polynucleate cells with dividing cells, and came to the conclusion, which we believe to be erroneus, that the normal method of vegetative reproduction was by multiple fission. Carter (1912) described a single division stage which she designated as a metaphase. From her description of the amoebae in the culture used it seems probable that the form was, as with Awerinzew, dubia. In fact she herself identified it as such. Taylor (1923) found no mitotic division, but pictured a series of peculiar nuclear forms that apparently lead to a form of division approaching amitosis. Levy (1924), who made a statistical study of the same species we used, secured probably from the same source, states that while he observed cell division he found no nuclei in his fixed preparations, but merely scattered granules, and suggests that during division a complete dispersal of the nuclear material occurs. Thus it is obvious that there is need for a careful and