THE UNIQUE MAMMAL 29 



complicated and intricate form of sociality j such, in fact, that no 

 individual or group could possibly avoid social relations. Pre- 

 dacity gave way to service j and altruism, not much heard of be- 

 fore, burgeoned to replace the protoplasmically grounded 

 selfishness of the biological struggle for existence. At least these 

 were the plain theoretical implications of this way of living. It 

 needs no pedantic elaboration of the matter to convey the sug- 

 gestion that in some respects the actual course of events has not 

 always closely followed the theoretical path. But these di- 

 vergences may best be left at this point for more ample discussion 

 later. The main point now is that the industrial-commercial- 

 service way of life has been, up to the present time, the culmina- 

 tion of the long process of setting man apart from all other ani- 

 mals as the unique mammal that we have so cursorily reviewed. 

 It is hoped that in this review one leading fact has been made 

 plain. It is that in the evolution of ways of getting a living the 

 trend of the progression has all along the route been from harder 

 to easier methods, insofar as concerns the expenditure of physical 

 (muscular) energy. Reflection suggests that it would perhaps 

 not be an unfair statement to say that biologically the develop- 

 ment of easier ways to get a living is on the whole the greatest 

 achievement of the human intellect. Looked at from an evolu- 

 tionary point of view the result appears to be congruent with 

 the general rule of organic nature that all living things tend to 

 get their livings with the minimum of effort possible under their 

 circumstances of life. Remembering that plants are just as much 

 and as truly living organisms as animals, it is an obvious and 

 somewhat overwhelming statistical fact that the vast majority of 

 living individuals on the earth are sessile — rooted to one par- 

 ticular geographical spot and spending none of their energies on 

 getting about. Incidentally it is worthy of note that it is among 

 these fixed and rooted plants that by far the longest individual 

 life spans are found. Various species of trees outlive many times 

 over any known multicellular animal. Evaluated by the im- 

 personal biological yardstick of survival the unbustling fixed 

 way of life would seem to be a good one. Later on in these 



