CHAPTER VIII* 

 ORGANIZATION 



WE have seen that the simplest living thing is a 

 formless speck of protoplasm, without distinctions of 

 structure, and therefore without distinctions of function, 

 all parts serving all purposes mouth, stomach, limb, 

 and lung indiscriminately. There is no separate 

 digestive cavity, no separate respiratory, muscular, or 

 nervous systems. Every part will successively feed, 

 feel, move, and breathe. Just as in the earliest state of 

 society all do everything, each does all. Every man is 

 his own tailor, architect, and lawyer. But in the prog- 

 ress of social development the principle of the division 

 of labor emerges. First comes a distinction between 

 the governing and governed classes; then follow and 

 multiply the various civil, military, ecclesiastical, and 

 industrial occupations. 



In like manner, as we advance in the animal series, 

 we find the body more and more heterogeneous and 

 complex by a process of differentiation, i.e., setting 

 apart certain portions of the body for special duty. In 

 the lowest forms, the work of life is carried on by very 

 simple apparatus. But in the higher organisms every 

 function is performed by a special organ. For example, 

 contractility, at first the property of the entire animal, 

 becomes centered in muscular tissue ; respiration, which 

 in simple beings is effected by the whole surface, is 

 specialized in lungs or gills ; sensibility, from j 



* See Appendix. 

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