LIFE AND OKGANISATIOK 85 



analogies of higher animal life, and more akin to the cha- 

 racters of the vegetable world. Even here no actual trans- 

 mutation has yet been made known ; and the argument we 

 have been stating remains therefore still untouched. But 

 we are bound to add, that much and able research is now 

 in progress, bearing on this question of the true definition 

 and limitation of species ; and followed chiefly through the 

 phenomena of breeding and hybrids, as the best and most 

 legitimate mode of approach to its solution. 



All these topics have close mutual kindred ; and we have 

 taken advantage of this, to bring into the foregoing argu- 

 ment many collateral topics illustrating the vocation and 

 spirit of modern science. We now come to another question, 

 linked into the same chain, viz., that of spontaneous or 

 equivocal generation; the enquiry whether new species 

 are still brought into existence, or have been so, within what 

 may be called the human period of life on earth ? We know 

 that certain species have utterly passed away within this 

 period; and that others are in assured progress towards 

 extinction. Man himself has been largely concerned as the 

 agent in these changes, whether of diminution or annihila- 

 tion ; but physical conditions have doubtless also had effect. 

 Is there anything in the nature of an equivalent to them, 

 by new acts of creation, or by the spontaneous production of 

 fresh forms of life ? 



Here again we are without a single fact in absolute proof. 

 The extinction of certain species (and these, as far as we 

 know, exclusively of the higher animal orders,) does in no 

 way imply the creation of others ; and the only affirmative 

 presumptions that can be offered are drawn from those minute 

 and obscure forms of life, where the sexual distinctions are 

 little marked, and the functions of reproduction of unwonted 

 kind. Accordingly, we find that those who hold this belief 

 dwell much upon the Entozoa ; and yet more on the appearance 



