PREFACE xi 



and life afterwards bestowed upon it, or whether the life of 

 the ovum originally inhered with the particles composing it ; 

 whichever of these alternatives is the true one is of no con- 

 sequence with respect to an investigation of the laws of life, 

 during those stages of existence in which life and matter are 

 united, and concur in their phenomena. It is x the object of 

 this work to sketch an analysis of some phenomena which are 

 produced by this co-operation. The terms employed to de- 

 signate the department of life are " vital properties, properties 

 of life, the vital principle^ the principle of life, the organic 

 spirit," &c. The two last only will require explanation. 

 By " the principle of life" it is meant to designate the collec- 

 tive properties of life : some properties, or one property, of life, 

 are terms which relate to an inferred analysis of the principle 

 of life. By the " organic spirit" it is meant also to designate 

 the collective, or aggregate, properties of life ; and this term 

 " spirit," which is almost obsolete, is chosen simply for the 

 reason that it ought not to be rejected, or to have become ob- 

 solete, since this term serves as well asany other to distinguish 

 inferred and invisible properties from those which are ob- 

 jects of the senses. This appears to be as much as is implied 

 by the old distinction between matter and spirit ; and my taste 

 is sufficiently gothic to prefer an old term to a new one, when 

 the old one has been disgraced without reason, and the new 

 one is a mere innovation, or an affected improvement, without 

 any real superiority. 



It will be perceived that the preliminary chapters are the 

 groundwork of the subsequent inquiry ; that an application 

 of the principles, laid down in these chapters, is constantly 

 brought in aid of the development of the principal subject ; 

 and consequently these chapters could not have been omitted 

 without the inconvenience of referring perpetually to doctrines 

 which were no where distinctly stated. If it be said that these 

 preliminary doctrines are pushed too far ; that it would have 

 been sufficient to have laid down the principles, and applied 

 them merely to the subject of physiology ; 1 reply, that their 

 universality, upon which alone their credit is supported, would 

 not have been thus physically demonstrated, and consequently 



