22 THE ARRANGEMENT OF THE 



On some amoebae during the locomotion the following obser- 

 vations can be made. Most favorable for this study are amoebas 

 containing a certain number of foreign bodies. The droplet of 

 the infusion should not be taken too large, as a floating amoeba 

 changes its shape, but not its place. The creeping begins after 

 the amoeba, if little fluid be present, reaches the surface of the 

 covering-glass or the slide. 



We notice that in a central portion of the body, near the 

 nucleus, the granules approach each other, slightly increasing in 

 size, and that foreign bodies accidentally present between them 

 are retained. At the periphery of the body corresponding to 

 the contracted portion, a bulging of a pale protrusion takes place 

 simultaneously 5 in this protrusion a delicate reticulum is, at 

 first, still recognizable. The more the protrusion bulges out, the 

 more it flattens on the surface of the glass, the more does the 

 reticulum fade, until there is left only a light, structureless flap. 

 In a moment, the foreign bodies then rush into the hyaline flap, 

 followed by a floating of the granules of the protoplasm,* and 

 the body of the amoeba, including the nucleus, is dragged toward 

 the protruded portion, which, meanwhile, has re-assumed the 

 reticular structure; in other words, the locomotion is accom- 

 plished. 



In infusions over one week old we find in almost every 

 amoeba coarse, shining granules, in varying number. The 

 nucleus of such an amoeba, which I briefly call an old one, often, 

 instead of looking homogeneous, contains one or several minute 

 cavities vacuoles. Such vacuoles sometimes appear in the body 

 of the amoeba, too, and each vacuole is seen bounded by a con- 

 tinuous thin layer of a shining substance. Not infrequently, 

 two vacuoles coalesce by the breaking of the thin separating 

 layer, and thus, at first, an hour-glass shaped, later, a roundish 

 cavity, is established. The vacuoles may disappear, as a rule, 

 suddenly, and in their place the reticulum becomes visible, just 

 as in the rest of the body ; sometimes within a vacuole, one or 

 more granules are seen in an oscillating motion. 



Upon placing a drop of glycerine at the edge of the covering- 

 glass, each amoeba contracts into a homogeneous, yellowish, 

 shining, and immovable lump the moment it is reached by the 

 glycerine. Here and there a small vacuole is perceptible in such 



* W. Kuehno has already observed the floating of .the granules in the 

 amoaba. Untersuchungen iiber das Protoplasma und die Contractilitaet. 

 Leipzig, 1864. 



