146 THE EVOLUTION OF MAN. 



are able to move, to eat, and to act entirely like Amoeba; 

 (Fig. 9). 



The capacity of the naked cell to make these character- 

 istic amoeboid movements depends on the contractility (or 

 automatic movableness) of the protoplasm. This seems to 

 be the universal property of all young cells. Where they 

 are not surrounded by a strong membrane, or shut up in a 

 " cell prison," they are all capable of amoeboid movements. 

 This is as true of the uncovered egg-cell as of other un- 

 covered cells, of the moving cells of various kinds, lymph- 

 cells, mucous cells, etc. 



Our examination of the egg-cell and comparison of it 

 with the Amoeba, has afforded us the best and surest basis 

 for the history of the germ as well as for the history of the 

 tribe. From it we have drawn the conclusions that the 

 human egg is a simple cell ; that this egg-cell is not essen- 

 tially different from those of other Mammals, and that we 

 must therefore infer the existence of a primeval one-celled 

 ancestral form, which in all essential points was of amoeboid 

 form. 



The assertion that the first ancestors of the human race 

 were simple cells of this sort, which, like the Amoeba, led 

 an independent one-celled life, has not only been ridiculed 

 as an empty scientific chimera, but has also been indig- 

 nantly rejected in theological periodicals as " horrible, 

 shocking, and immoral." But, as I have already remarked 

 in my lectures "On the Origin and Genealogy of the Human 

 Race," the same righteous indignation must fall with equal 

 justice on the "horrible, shocking, and immoral" fact, that 

 every human individual develops from a single cell, and 

 that this human egg-cell cannot be distinguished from 



