SUGGESTIONS.--Amebas live on the slime found on submerged stems and leaves in standing water, or in the ooze at the bottom. Water plants may be crowded into a glass dish and allowed to decay, and after about two weeks the ameba may be found in the brown slime scraped from the plants. An ameba culture sometimes lasts only three days. The most abundant supply ever used by the writer was from a bottle of water where some oats were germinating. Use ¹⁄₅ or ¹⁄₆ inch objective, and cover with a thin cover glass. Teachers who object to the use of the compound microscope in a first course should require a most careful study of the figures. [Illustration: FIG. 9.--AMEBA PROTEUS, much enlarged.] [Illustration: FIG. 10.--AMEBA. _cv_, contractile vacuole; _ec_, ectoplasm; _en_, endoplasm; _n_, nucleus; _ps_, pseudopod; _ps′_, pseudopod forming; ectoplasm protrudes and endoplasm flows into it.] =Form and Structure.=--The ameba (also spelled amœba) looks so much like a clear drop of jelly that a beginner cannot be certain that he has found one until it moves. It is a speck of protoplasm (Fig. 9), with a clear outer layer, the _ectoplasm_; and a granular, internal part, the _endoplasm_. Is there a distinct line between them? (Fig. 10.) Note the central portion and the slender prolongations or _pseudopods_ (Greek, false feet). Does the endoplasm extend into the pseudopods? (Fig. 10.) Are the pseudopods arranged with any regularity? Sometimes it is possible to see a denser appearing portion, called the _nucleus_; also a clear space, the _contractile vacuole_ (Fig. 10). =Movements.=--Sometimes while the pseudopods are being extended and contracted, the central portion remains in the same place (this is _motion_). Usually only one pseudopod is extended, and the body flows into it; this is _locomotion_ (Fig. 11). There is a new foot made for each step. [Illustration: FIG. 11.--The same ameba seen at different times.] =Feeding.=--If the ameba crawls near a food particle, the _pseudopod is pressed against it_, or a depression occurs (Fig. 12), and the particle is soon embedded in the endoplasm. Often a clear space called a _food vacuole_ is noticed around the food particle. This is the water that is taken in with the particle (Fig. 12). The water and the particle are soon absorbed and assimilated by the endoplasm. [Illustration: FIG. 12.--THE AMEBA taking food.] =Excretion.=--If a particle of sand or other indigestible matter is taken in, _it is left behind_ as the ameba moves on. There is a clear space called the _contractile vacuole_, which slowly contracts and disappears, then reappears and expands (Figs. 9 and 10). This possibly aids in excreting oxidized or useless material. =Circulation= in the ameba consists of the movement of its protoplasmic particles. It lacks special organs of circulation.