GENERAL ZOOLOGICAL FACTS AND THEORIES 303 



tations as to method of movement, is as free to vary its relations 

 to the environment in response to a stimulus as an organism of its 

 form and structure could conceivably be. Such behavior does 

 not fall within the concept of a reflex if the latter is defined as a 

 uniform reaction " (246, p. 279). Jennings has pointed out that 

 before the reflex can be considered a simple invariable unit for 

 behavior, the physiological condition of the organism must be 

 taken into account. Such a unit might be illustrated as follows: 

 stimulus A, acting upon an animal whose physiological state is 

 B, gives reaction C. 



b. Instinct 



Instinct is " the faculty of acting in such a way as to produce 

 irtain ends, without foresight of the ends, and without previous 

 lucation in the performance " (James). Instinctive acts are 

 complex. They are performed in a similar manner by all 

 lembers of the same sex and race. Those of the social animals 

 remarkably varied. Our study of the honeybee (Chap. XII) 

 given us sufficient knowledge of this insect to warrant our 

 sing it to illustrate certain kinds of instincts. 

 The queen's nuptial flight and her copulation with the drone is 

 istinctive. She acts without previous experience, and accom- 

 lishes the filling of her spermatheca with spermatozoa without 

 apparently realizing the purpose of the whole performance. The 

 selection of a hollow tree by worker scouts, and the cleaning of it 

 in preparation for the swarm, is instinctive. The many activities 

 that follow the advent into a new home, such as crevice chinking, 

 varnishing, wax forming, comb building, egg laying, gathering 

 and storing pollen and nectar, ripening honey, guarding, cleaning, 

 and ventilating the hive, and caring for the queen and young 

 bees, are the results of instincts. 



The instinct of caring for the young is of special interest, since 

 those animals that care for their young succeed in rearing a larger 

 proportion than those that allow their offspring to shift for them- 



