56 THE HISTORY OF CREATION. 



most important of all organisms to the whole science of 

 biology, and especially to general genealogy. For it is 

 evident that the Amoebae originally arose out of simple 

 Monera (Protamoebse), by the important process of segre- 

 gation taking place in their homogeneous viscid body — the 

 differentiation of an inner kernel from the surrounding 

 ])lasma. By this means the great progress from a simple 

 cytod (without kernel) into a real cell (with kernel) was 

 accomplished (compare Fig. 8 A and Fig. 10 B). As some of 

 these cells at an early stage encased themselves by secreting 

 a hardened membrane, they formed the first vegetable cells, 

 while othex's, remaining naked, developed into the first 

 aggregates of animal cells. The presence or absence of an 

 encircling hard membrane forms the most important, 

 although by no means the entire, difference of form between 

 animal and vegetable cells. As vegetable cells even at an 

 early stage enclose themselves within their hard, thick, and 

 .solid cellular shell, like that of the Amoebse in a state of rest 

 (Fig. 10 A), they remain more independent and less accessible 

 to the influences of the outer world than are the soft animal 

 cells, which are in most cases naked, or merely covered by a 

 thin pliable membrane. But in consequence of this the 

 vegetable cells cannot combine, as do the animal cells, for 

 the construction of higher and composite fibrous tracts, for 

 example, the nervous and muscular tissues. It is probable 

 that, in the case of the most ancient single-celled organisms, 

 there must have developed at an early stage the very im- 

 portant difference in the animal and vegetable mode of 

 receiving food. The most ancient single-celled animals, being 

 naked ceUs, could admit solid particles into the interior ()f 

 their soft bodies, as do the Amcebse (Fig. 10 B) and the 



