Tribal Life. 53 



cell is a store ot potential energy, while the male is a store 

 of kinetic energy, which acts as a liberating energy on the 

 female cell, permitting of the transference of its potential 

 into kinetic energy. 1 In certain rare cases the female cell 

 has the power of developing without previous union with 

 the male cell. This is known as parthenogenesis. 



These two methods of reproduction are usually conjoined, 

 especially in the vegetal kingdom, save in very low forms of 

 life, where, so far as we know, asexual reproduction alone 

 exists. Sexual reproduction prevails more generally among 

 the highest forms of life, especially in the animal world. 



After fertilisation (as sexual union is termed) of the 

 female cell by the male, the female cell may be considered 

 as and styled an embryo. The embryo passes through a 

 variety of stages, sometimes very extraordinary in their 

 nature, before arriving at the adult condition. The history 

 of these successive changes is termed its ontogeny, or 

 individual life-history. It is, moreover, apparent that every 

 organism must have a genealogy or tribal history in addition 

 to its individual history. To the genealogical history the 

 term phytogeny is applied. 



As a result of the brilliant researches of biologists during 

 the past century, amongst whom Lamarck, Geoffrey St. 

 Hilaire, Haeckel, Darwin, and Wallace hold the first places, 

 a definite relation has been established between these two 

 histories. In an elementary text-book like the present, it 

 would be entirely out of place to go into this subject with 

 requisite detail ; it will be sufficient to state briefly that 

 there is abundant evidence to show that the ontogeny of 

 any organism is an epitome of its own phylogeny, and that 

 the various stages in its development indicate landmarks 

 guiding us in the tracing of its genealogical history each 



1 Probably the male cell at the same time brings to the female cell 

 certain chemical compounds necessary for the further development of 

 the ovum. 



