Living organisms are characterized by a complex and beautiful organized pattern of chemical reactions mediated and directed by enzyme systems. These reactions provide the energy necessary for the various functions of the cell and support the synthesis of materials upon which the cell depends for maintenance, growth, and multiplication. The introduction of an inhibitor into the system leads to an alteration of the rates of certain processes and a disturbance of the balance of the chemical and functional activities. If the inhibitor shifts the balance to the detriment of the organism, it is generally classed as a poison or a toxic chemical; when the balance is shifted in favour of the survival of the total system, the inhibitor may be considered as a drug...