ANATOMY OF THE CELL. 7 
the current is continued, the surplus escapes from between the 
micellae and collects in some part of the cell where it forms a 
vacuole. ‘This is rendered possible by the nature of the cell 
wall, which at this stage of growth is not only flexible but 
elastic. If only one vacuole is formed, it usually occupies the 
central portion of the cell, and as it increases in size, presses 
back the protoplasm against the wall so that the protoplasmic 
contents now assume the form of a layer of greater or less 
Fie. 1. 
Cell with nucleus n near the 
wall. The vacuole p con- 
tains cell sap by which 
Fig. 2. 
the protoplasmic body is Protoplasm in fine strings 
pressed back against the Protoplasm containing sey- running through cavities 
wall causing turgescence.— eral vacuoles, nucleus cen- containing cell sap. — 
Theodore Hartig. tral. —(T. H.) (TEP) 
thickness, lining the wall and pressing firmly against it. In 
such cases the nucleus lies imbedded in this layer and is 
therefore called lateral. 
If several vacuoles are formed at the same time, the nucleus 
remains near the centre of the cell between the vacuoles but 
always surrounded by protoplasm. When the vacuoles are 
large the protoplasm between them becomes reduced to mere 
threads, so that the central portion appears crossed by fine 
filaments. Outward against the cellulose wall, as well as in- 
ward toward the cell-sap, the protoplasm is bounded by a very 
1 The name primordial utricle is sometimes applied to this layer of proto- 
plasm, but the term is falling into disuse and the different parts of the proto- 
plasmic mass have received new names corresponding with their nature. 
