=Feeling.=--_Jarring_ the glass slide seems to be felt, for it causes the activity of the ameba to vary. It does not take in for food every particle that it touches. This may be the beginning of _taste, based upon mere chemical affinity_. The pseudopods aid in feeling. =Reproduction.=--Sometimes an ameba is seen dividing into two parts. A _narrowing_ takes place in the middle; the _nucleus also divides_, a part going to each portion (Fig. 13). The mother ameba finally divides into two daughter amebas. Sex is wanting. [Illustration: FIG. 13.--AMEBA, dividing.] =Source of the Ameba’s Energy.=--We thus see that the ameba moves without feet, eats without a mouth, digests without a stomach, feels without nerves, and, it should also be stated, breathes without lungs, for _oxygen is absorbed_ from the water _by its whole surface_. Its _movements require energy_; this, as in all animals, is furnished by the _uniting of oxygen with the food_. Carbon dioxid and other waste products are formed by the union; these pass off at the surface of the ameba and taint the water with impurities. =Questions.=--Why will the ameba die in a very small quantity of water, even though the water contains enough food? Why will it die still quicker if air is excluded from contact with the drop of water? The ameba never dies of old age. Can it be said to be immortal? According to the definition of a cell (_Chapter I_), is the ameba a unicellular or multicellular animal? =Cysts.=--If the water inhabited by a protozoan dries up, it encysts, that is, it forms a tough skin called a cyst. Upon return of better conditions it breaks the cyst and comes out. Encysted protozoans may be blown through the air: this explains their appearance in vessels of water containing suitable food but previously free from protozoans. THE SLIPPER ANIMALCULE OR PARAMECIUM =Suggestions.=--Stagnant water often contains the paramecium as well as the ameba; or they may be found in a dish of water containing hay or finely cut clover, after the dish has been allowed to stand in the sun for several days. A white film forming on the surface is a sign of their presence. They may even be seen with the unaided eye as tiny white particles by looking through the side of the dish or jar. Use at first a ¹⁄₃ or ¹⁄₄ in. objective. Restrict their movements by placing cotton fibers beneath the cover glass; then examine with ¹⁄₅ or ¹⁄₆ objective. Otherwise, study figures.