A TEXTBOOK OF PHYSIOLOGY 



BOOK I 

 GENERAL PHYSIOLOGY 



CHAPTER I 

 BIOLOGICAL INTRODUCTION 



LIVING in the stagnant water of most ditches is the tiny animalcule 

 known as the Amoeba (Fig. 1). If a drop of water containing this little 

 organism be placed on a slide beneath the lens of a microscope, exami- 



c.v. 



*-! 



FIG. 1. AMCEBA PROTEUS, AN ORGANISM CONSISTING OF A SINGLE NAKED CELL. 

 X 280. (Redrawn after Sedgwick and Wilson.) 



N, Nucleus; w.v., water- vacuoles ; c.v., contractile vacuole ;/.?;., food vacuole. 



nation shows that the tiny animal consists of a mass of semi-fluid 

 material known as protoplasm. Scattered in this semi-fluid mass 

 are a number of granules ; at one spot the: e is an empty space, the con- 

 tractile vacuole ; while in the centre is a round, more highly specialized 



1 



