ANIMALS, THEIR SIZES, ETC. 67 



these atoms is differentiated into "the inner nucleus 

 (caryoplasm) " and "the body of the cell (cyto- 

 plasm).' (Haeckel, Ev. Man, p. 38.) Again he says: 

 "In a mesh of the nuclear net-work * * * * there 

 is, as a rule, a dark, very opaque, solid body, called 

 the nucleolus.' (Ev. Man, p. 38.) On another page, 

 he says: "Some cells have a 'nucleolinus* in the cen- 

 ter of the nucleolus." (Ev. Man, p. 40, fig. 9.) 



We cannot believe that any microscopic cell, in 

 the human body has intellect, memory, will-power nor 

 creative force. For a stronger reason, we cannot im- 

 agine that any of the atoms of which any cell is com- 

 posed, has these faculties. Nor can we conceive that 

 a portion of these atoms, automatically, metamorphose 

 themselves into a nucleolus, others into a nucleolinus, 

 while the remainder continue to be a simple cell-body. 



How do the cells know when the time has come 

 to divide into two daughter-cells; where the dividing 

 line should run in order to divide the cell-body, nu- 

 cleus and nucleolus into two equal parts? For further 

 discussion of cells see Index, infra, "cell." 



Sec. 24. Animals, Their Sizes are Deter- 

 mined, How? 



Why does the elephant grow larger than the 

 mouse. Both are mammals and are built of cells. The 

 mouse has identically the same organs and parts that 

 the elephant has. The mode of reproducing each is 

 the same as that of the other. The spermatozoon, 

 ovum and germ-cell are common to both. 



