VITAL PKINCIPLE. 23 



able us to accomplish this task. It scarcely warrants us to 

 hope that the object is attainable. We know, however,, 

 that the following circumstances are invariably present, 

 whenever the vital principle begins to exhibit its move- 

 ments. 



1. A Parent.- Previous to the independent existence of 

 a plant or animal, it is necessary that they shall have form- 

 ed a part of some other body similar to themselves. This 

 condition is ascertained in so satisfactory a. manner, in the 

 case of the more perfect organized beings, as to preclude 

 the possibility of a doubt. There are, .however, many 

 plants and animals, with whose manner of growth and 

 mode of propagation, we are so imperfectly acquainted, 

 that we must rely upon the evidence of analogy for the 

 conclusions which we form with respect to their origin. 

 But as all the living bodies whose history has been stu- 

 died with care, have evidently participated in the existence 

 of other living bodies, before they exercised the functions 

 of life for themselves, the presumption, that the same kind 

 of generation takes place in every organized body, offers all 

 the claims of a legitimate deduction. Life,, then, may be 

 considered as proceeding from life, as transmitted from one 

 individual to another, .and as dating its actual origin from 

 the period when the voice of Omnipotence uttered the 

 words, " Let the 3Earth bring forth. 1 



The ancients, whose opinions respecting the nature of 

 generation were necessarily obscure, from the want of pro- 

 per instruments . and methods of observation, considered 

 living bodies as produced in two different ways. In the 

 ,rst, exemplified in the case of the more perfect animals 

 , and vegetables, they considered organized -bodies as pro- 

 ceeding from other organized bodies, by a process which is 

 termed Univocal or Regular Generation. In the second, 

 they supposed that the putrefaction of different bodies, 



