CHAPTEE I 



INTEODUCTION 



Protoplasm is the name given to that colloidal, jelly-Uke 

 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 cells, and with very few exceptions 

 each cell contains one or Hciore speciaUsed portions of proto- 

 plasm which take up staining material more readily than the 

 body of the cell, and which are termed nvdei. An organism 

 may consist of but one ceU 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 



1 



