54 READINGS IN BIOLOGICAL SCIENCE 



organs for their performance. Among such are the pollen basket on the 

 hind legs of the hive bee, the pollen combs, the wax glands on the under- 

 side of the abdomen, and the peculiar wax pincers by which the scales of 

 wax are removed. The whole structure and instinctive behavior of the 

 worker bee have been profoundly modified in relation to the accessory 

 nutritive activities upon which she unselfishly spends so much of her en- 

 ergies. We thus see how, in relation to the primitive function of nutrition, 

 one complication leads on to another, and this again to a third, and so on. 

 The basic vital process of (A) absorption becomes associated with the 

 preliminary and preparatory activities of (B) digestion. These may finally 

 involve. elaborate mechanisms for their discharge, but subsidiary to these 

 there are worked in (C) specialized modifications of the muscular and 

 nervous systems, to say nothing of other parts. Subsidiary activities of 

 collecting food, involve often, complicated structures and modes of be- 

 havior, and subsidiary to these, again, we have (E) such acts as web spin- 

 ning and comb making, and many others, each entailing more or less ex- 

 tensive changes of structure and behavior. In this way life becomes more 

 and more complex. 



We see much the same sort of thing exemplified in the development of 

 industry. One may manufacture such articles as cigarettes with a very 

 simple layout. A few girls with very simple apparatus could turn out a 

 goodly number of these articles in a day. But if a primitive plant should 

 grow into a large factory, we would find the installation of more complex 

 machinery and no end of accessory activities. There would be janitors, 

 bookkeepers, stenographers, business managers, traveling salesmen, special 

 buyers, pay clerks, advertisers, night watchmen, and perhaps attorneys 

 and plain clothes detectives, all of whom would be engaged in work sub- 

 sidiary, directly or indirectly, to the fundamental function of the factory. 

 Although the basic function of nutrition may be a more complicated proc- 

 ess than making cigarettes, it comes to require in special cases a vast deal 

 of machinery to carry out the subordinate activities and the activities sub- 

 sidiary to these, and so on to the spinning of the spider's web and the build- 

 ing of the comb of the hive bee. 



It would be instructive to consider another illustration of how compli- 

 cations pile up in the evolution of life, and this time I will select the process 

 of reproduction, which is certainly a basic vital function characteristic of 

 all species of living organisms. Its simplest manifestation is in the fission 

 of a very primitive form of life, such as a bacterium. The propagation of 

 all but the simplest of the one-celled organisms commonly involves in 

 some part of the life cycle the intervention of sex. So far as is known, the 

 bacteria, the blue-green algae and some other groups are primarily sex- 

 less. Doubtless, life existed on the globe for many millions of years before 

 sex entered upon the scene, but it is a significant fact that it never evolved 

 very far. One might indulge in flights of fancy as to what plants and animals 



