30 PHARMACEUTICAL BOTANY 
Still more primitive and less differentiated are the Amoeba, 
the vegetative stages or plasmodia of slime moulds, and the 
bacteria which, along with many other unicellular organisms 
of simple structure, have been called ‘‘Protista.”’ It is the belief 
of most biologists that plants and animals of the present day 
have gradually developed from a common origin which, during 
an early era in the earth’s history, gave rise to the Protista from 
which arose two diverging branches of organisms known as the 
plant and animal kingdoms. 
It is impossible to draw sharp lines of distinction which will 
separate all plants from all animals owing to the similarity of 
structures, functions and laws of inheritance found in organisms 
belonging to both groups. It is possible, however, to find points 
of difference between most plants and most animals. These are 
given in the table on page 29. 
PROTOPLASM AND ITs PROPERTIES 
Protoplasm, or living matter, is the viscous cell substance in 
which life resides. Huxley has defined it as the “‘physical basis 
of life.” 
Protoplasm occurs as a colloidal solution and as an emulsion 
of colloidal particles. It has well been called a ‘polyphase 
colloidal system.’ Colloids are substances like glue, agar or gelatin 
which do not crystallize when solidifying from solution and 
which will not pass through a semipermeable membrane like 
pig’s bladder or parchment. Substances like salt and sugar 
which crystallize from a solution upon evaporation of the solvent 
and which pass through a semipermeable membrane are called 
- erystalloids. When examined under the microscope, proto- 
plasm appears either as a colorless jelly in which are frequently 
imbedded globules and granules of various shapes and sizes or as 
a streaming liquid. It occurs both as a sol or liquid that flows 
readily or as a gel or jelly-like mass. It is extremely complex 
and unstaple. It may change from the liquid to the jelly state or 
vice versa under certain conditions. The liquid portion of the 
protoplasm contains particles of ultramicroscopic size while the 
jelly-like, granular portion contains particles, granules or 
globules visible under a compound microscope. 
