CHAPTER I 
INTRODUCTION 
PROTOPLASM is the name given to that colloidal, jelly-like 
substance which forms the basis of all life on this globe. 
Every living organism consists of protoplasm and the products 
of protoplasm. Whilst life lasts it is continually renewed 
from food which passes into the organism, and which, by 
the action of the protoplasm already there, is built up into 
new protoplasm. At the same time other portions of the 
protoplasmic body of the organism are being broken down, 
and the products thus formed are either thrown out from the 
body as excreta, or remain in the body, either stored away as 
useless, or in most cases performing some useful function, such 
as that of protecting the organism by forming a cyst or shell 
or internal skeleton. 
The protoplasm of living beings is arranged in a series of 
units or elements, termed cel/s, and with very few exceptions 
each cell contains one or more specialised portions of proto- 
plasm which take up staining material more readily than the 
body of the cell, and which are termed nuclez. An organism 
may consist of but one cell with its nucleus or nuclei, but 
more commonly it is composed of an enormous number of 
cells, connected together, and each dominated by a single 
nucleus. In either case, whether the organism is unicellular 
or multicellular, the cell is capable of an extraordinary degree 
of differentiation, and may assume the most diverse forms. 
In the multicellular beings similar cells are massed together 
into aggregates which form the various tissues composing the 
body of the higher organisms. In unicellular forms the cells 
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