322 TOWARDS THE HUMAN FORM 



human form and mental character would appear to have been 

 essentially brought about by the progress of the intelligence. 

 It must have been at a very early date that the development of 

 man's ancestors was orientated in this direction. 



Once past the lemurian stage, which in Adapids was still 

 one that had links with the Marsupials, it would appear that 

 the simple erection of the body into the vertical position, 

 without any modification of the structural type, at once opened 

 the way that was to lead rapidly to the human form by the 

 uninterrupted and almost exclusive progress of the organs of 

 intelligence and reason. Elsewhere, limbs, dentition, 

 tegumentary dependencies, and visceral organs themselves 

 were modified in all directions, especially adapting themselves 

 to purely material functions. Here, on the contrary, effort was 

 concentrated in the perfecting of the nervous system and the 

 cerebral apparatus, so that Man, separated at the outset from 

 existing members of the Monkey tribe, has no direct relation- 

 ship with any other Mammal. 



Is this to claim on behalf of Man, from a purely material 

 viewpoint, a place apart in nature ? Every fact set down in 

 this book leads to a contrary conclusion. Following the 

 example of the geologists, who, refusing to attribute the 

 explanation of the configuration and structure of the globe 

 to unknown causes, have succeeded so brilliantly in explaining 

 all by a unique consideration of the causes yet at work around 

 us, I have sought to establish that laws still regulating life 

 are adequate to explain the formation and evolution of the 

 principal organic types — a problem that seems to me of greater 

 importance than the pursuit of the factors determining 

 variation of species, which is but a fractional part of the main 

 problem. 



Thus the human form explains itself like the others. It would 

 seem, indeed, that across the fluent sea of living forms those 

 that set their course towards the human type have left a wake 

 that is wonderfully direct. Sponges, Polyps, Bryozoa, 

 Arthropods, Flat-worms, Star-fish and the world of 

 Echinoderms to which they give rise, Molluscs, Tunicates, 

 Bony Fishes, tailless Batrachians, Reptiles, Birds, hoofed 

 and clawed placental Mammals — all these are off that main 

 track. Moreover, whereas purely mechanical conditions or 

 attitudinal changes have led to the early forms and subsequent 



