20 INTRODUCTION. 



exercising upon the elements which compose a 

 living body, and upon the particles which it attracts, 

 an action contrary to that which ordinary chemical 

 affinities would produce without it, affords us a con- 

 faculty. This is at once an admission that the properties of mat- 

 ter alone cannot give rise to the formation of the generative organs, 

 nor to their functions, and, consequently, that we must look to 

 some specific principle which, from its influence, has been called a 

 vital principle, as the necessary adjuvant of organization, and of 

 the operations which organized bodies present. Indeed, expe- 

 rience sufficiently shows us that generation, in some of its forms, 

 is peculiar to living bodies ; that it is a process essentially vital ; 

 that it is a transfer or emanation of part of the life of the parent 

 to the ovum ; and that no similar phenomenon presents itself amid 

 the changes to which inanimate matter is subject. Our endea- 

 vours to trace the origin of vital actions bring us naturally to this 

 process, and from it we mount to the inference of an original 

 parent, which at some remote period received its being from a 

 first cause. 



From our attempts to investigate the generative processes, we 

 have every reason to infer, that the embryo or germ is endowed 

 with vitality before its organs become fully formed, and that the 

 organs can only be perfected by means of this influence. The ova 

 of animals and the seeds of plants are evidently supplied with this 

 principle, for they withstand, for a longer or shorter period, the 

 external causes of change, and the operations of the affinities and 

 laws which characterize inorganized matter. But, although we 

 thus contend that the embryo (whatever may be its form or con- 

 dition) is endowed with vitality, we cannot suppose that it pos- 

 sesses, the various organs and textures essential to its future exist- 

 ence in a state of perfection ; indeed, we have positive knowledge, 

 that a perfect organization does not obtain at this early period of 

 the existence of the offspring. All that we know is, that the 

 embryo is produced from the parents in the simplest, but at the 

 same time most imperfect, state of organization ; that certain uni- 

 form phenomena, which it presents, shew it to possess an influence 

 or principle which counteracts and controls the affinities of the 

 elements with which it is allied, and that the earliest periods, at 

 which its organization becomes a matter of demonstration, present 



