84 THE MICROSCOPE. 



two beings are again produced identical in spe- 

 cies with the two beings from which the two 

 fecundating elements, above-mentioned, were 

 first derived. 



" The first set of changes is, in all animals, of 

 the same kind, and consists in the formation of 

 a vital germinal cell, and its propagation of a 

 numerous offspring by repeated spontaneous di- 

 visions. . . . Among the higher vertebrate animals 

 all the derivative germ-cells are employed in the 

 formation of the foetal tissues and organs, and 

 all the foetal changes up to the moment of full 

 development are represented in one simple 

 cycle. Not so, if we descend low on the organic 

 scale. All the germ-cells are not employed in 

 laying down the embryonic tissues. Part o 

 them, with their full spermatic power, are en- 

 tangled among the tissues, t and by virtue of 

 their assimilatives and fissiparous forces lay the 

 foundation of a new organism/ (Owen on Par- 

 thenogenesis, p. 31.) In this way we not merely 

 state a fact, but we give a physiological reason 

 for it (compatibly with elementary vital laws), 

 when we say that a new form of larval life may 

 spring from a previous larva by Parthenogenesis 

 i. e.j without sexual union : but at the same 



