Peptides, Hormones, and Behavior

Fundamental to survival of living organisms is their ability to react appropri­ ately to their environment. Cannon (1929) recognized that "back of internal homeostatic mechanisms are powerful motivating agencies-appetites and hunger and thirst." Almost all observed behavior may be viewed as activity required to meet some physical or emotional need. "The higher in the scale of living things, the more numerous, the more perfect, and the more compli­ cated do these regulatory agencies become."...