40 
PHARMACEUTICAL BOTANY 
tain its identity while all the matter of which it is composed is 
changed over and over. It is like a whirlpool or wave in a river 
which remains the same while the water of which it is composed 
changes continually. Metabolism has been aptly defined by Huxley 
as the whirlpool character of the organism. 
3. Reproduction.- — Protoplasm also shows a very remarkable 
ability to increase and to give off detached portions which retain 
the infinitely complex peculiarities and properties of the original. 
The process, moreover, may be continued indefinitely. 
Other physiological characteristics might be added, but the above 
are mentioned as the most satisfactory criteria by which living may 
be distinguished from non-living matter. 
PROTOPLASMIC CELL CONTENTS 
Protoplasm consists of four well-differentiated portions: 
(a) Cytoplasm, or the foamy, often granular matrix of protoplasm 
outside of the nucleus. 
(b) Nucleus or Nucleoplasm, a denser region of protoplasm con- 
taining chromatin, a substance staining heavily with certain basic 
dyes. 
( c ) Nucleolus, a small body of dense protoplasm within the 
nucleus. 
(d) Plastids, composed of plastid plasm, small discoid, spheroidal, 
ellipsoidal or ribbon-shaped bodies scattered about in the cytoplasm. 
Sometimes, as in the cells of lower plants like the Spirogyra, plastids 
are large and are then called chromatophores. 
According to the position of the cells in which plastids occur and 
the work they perform, they differ in color, viz.: 
Leucoplastids are colorless plastids found in the underground 
portions of a plant and also in seeds, and other regions given up to 
the storage of starch. Their function is to build up reserve starch 
from sugar and other carbohydrates as well as to change the reserve 
starch back into sugar when it is needed for the growth of the plant. 
They are only evident after properly fixing and staining cells con- 
taining them. 
Chloroplastids are plastids found in cells exposed to light and con- 
tain the green pigment, chlorophyll. 
