GENESIS OF MAN. 27 



Mathematically enunciated, the germ-development becomes a 

 function of the race-development, so that every differentiation of 

 the latter carries with it a corresponding and consequential differ- 

 entiation of the former. This is the fundamental law of organic 

 development, the great biogenetic ground-principle, to which the 

 student of the history of development, whether of its ontogenetic or 

 its phylogenetic aspect, must continually recur. The law of 

 heredity, which Goethe calls " the stubborn power of permanency in 

 whatever has once possessed reality," while it graciously yields to 

 the influence of surrounding circumstances and admits of progress, 

 nevertheless requires, with all the rigor of sovereignty, that every 

 step forward shall be taken through the established channels, and 

 with due respect for the most ancient forms. The human germ may, 

 indeed, develop and perfect itself in the highest form of organized 

 existence, but the old and time-honored fish-form and worm-form 

 and amoeba-form, nay, even the moner-form, must be respected, and 

 the proud man-germ must humbly bow to the inexorable decree of 

 Nature, and must undergo this manifold and repeated metempsycho- 

 sis, which in its strange reality eclipses all the dreams of Thales 

 and Pythagoras. 



Phylogenesis, which is a cause, begins with the inoner ; onto- 

 genesis, which is a consequence, begins with the cell. For man, 

 as for all animals that have advanced beyond an extremely low 

 stage of existence, there is but one mode by which new individuals 

 of the race can be created and the race itself perpetuated, and that 

 is by the contact of two germinal principles having opposite sexual 

 polarities. Each of these principles is a simple cell. The male is 

 the sperm-cell, the female the germ-cell. Only by the union and 

 literal blending of these two cells can generation take place, 



The cell is the lowest organized form of existence. It is also 

 the last term in the histological analysis of the tissues of the body. 

 An animal is ultimately nothing more than an organized assem- 

 blage of cells, a compound individual. 



The moner is a lower form of existence than the cell, the low- 

 est known form, and may be distinguished as a wholly unorganized 

 and undifferentiated individual. 



There are but two essential properties of a cell, a central nucleus 

 and surrounding protoplasm. The only organization, the only differ- 

 entiation, is that which distinguishes these two substances. And 



