THE CHARACTERISTICS OF HUMAN LIFE 47 



more than organism remains to be seen. All that is 

 required of us here is to make account of structural 

 diversity, specially as this may appear in terminal 

 arrangements for organs of special sense. There is close 

 resemblance in embryological development, and again 

 in the functions of the mature life. Yet each germ-cell, 

 though unfolding through analogous forms, develops 

 the life of the species to which it belongs. At the 

 moment of birth, the distinctive species is manifest. 

 In the activity which thenceforth begins, analogous 

 functions, and distinctive functions, are readily 

 recognised. The functions of the vital organs, of 

 respiration, digestion, circulation; the functions of 

 the sensori-motor system ; the functions of the special 

 senses, touch, smell, taste, hearing, and sight; the 

 functions of the brain in receiving and transmitting 

 excitation, are fundamentally analogous. At the 

 same time, the specialities of the human species 

 appear in the infant, coming more clearly in view 

 as infant life unfolds. All this concerns a phy 

 sical life. Here, therefore, it is sufficient to employ 

 language applicable to material existence, for we refer 

 exclusively to physical organs and physical functions. 

 Let us remember, that organism is, strictly speaking, 

 a constructed machine, with apparatus adapted to 

 secure certain ends. When it is added that the 

 machine is in all cases constructed on a common 

 plan, it is obvious that this is natural if the several 

 organisms are to accomplish common ends. This 

 conclusion is sure, the human body is constructed on 

 a common plan applicable to animal life. From the 

 first movement in the fertilised egg, onwards to the 

 date of birth, the human organism passes through 



