122 THE ANATOMY OF THE HONEY BEE. 



X. THE NERVOUS SYSTEM AND THE EYES. 



We have learned so far that the bee is a complex animal made up 

 of a large number of tissues and organs all definitely interrelated, and 

 we speak of these tissues and organs as performing their own special 

 functions. Yet, in itself, a mass of cells, even though a living mass, 

 is incapable of doing anything — it is inert unless stimulated into ac- 

 tion. The legs would not move, the heart would not beat, the glands 

 would not secrete, the respiratory movements would not be produced, 

 and the animal would cease to live were it not for a vital force that 

 incites them all into activity. This force is generated by certain 

 cells of the nervous system and is sent out to the other organs along 

 the nerve cords, but we know nothing more about it than simply that 

 it exists in living animals and is dependent upon the maintenance of 

 the nerve cells. 



Now, in order that an animal may be " alive," it is not only neces- 

 sary that the muscles should be made to contract, the glands to secrete, 

 and all the other organs induced to perform their individual roles, 

 but it is equally important that they should all work together and 

 accomplish definite results. The muscles must perform harmonious 

 movements to produce walking, flying, breathing, or swallowing, the 

 heart must beat in proper rhythm, the glands must secrete their juices 

 at the right time and in needed amounts. Hence, the functions both 

 of stimulation and coordination devolve upon the nervous system. 

 The nerve-cells generate a force which, delivered through the nerve- 

 fibers to the various organs, irritates the tissues into activity, but, at 

 the same time, the cells send out this force in such a methodical man- 

 ner that the activities produced in the different organs are definitely 

 correlated and cooperate in maintaining the necessary condition for 

 the life of the cells. 



The nervous system, however, is more than simply the source of 

 these physical and chemical processes that constitute the visible phe- 

 nomena of life, for it is also the seat of all sense perceptions and, in 

 the higher animals, of consciousness. We do not know, however, that 

 insects possess consciousness — ^that they are actually aware of their 

 own existence, and we therefore do not know that they have conscious 

 sense perceptions. We do know that they are affected by external 

 objects — ^by light, heat, taste, odor, pressure, and perhaps sound 

 acting upon specially sensitized cells of the ectoderm called sense 

 organs, but we do not know that the reaction of the individual is 

 anything more than the exhibition of a very highly developed re- 

 flex nervous system. It is most probable that bees do all that they 

 do — make the comb, store up honey and pollen, feed the young, attend 

 to the wants of the queen, and so on — ^without knowing why, and we 

 have no evidence that they are even conscious of the fact that they do 



