618 THE REPRODUCTIVE FUNCTIONS. 



Struck with the numerous forms of transition 

 through which every organ has to pass before 

 arriving at its ultimate and comparatively per- 

 manent condition : we cannot but wonder at the 

 vast apparatus which is provided and put in 

 action for effecting all these changes ; nor can 

 we overlook the instances of express contrivance 

 in the formation of so many temporary struc- 

 tures, which are set up, like the scaffold of an 

 edifice, in order to afford the means of trans- 

 porting the materials of the building in propor- 

 tion as they are wanted ; nor refuse to recognise 

 the evidence of provident design in the regular 

 order in which the work proceeds, every organ 

 growing at its appointed time, by the addition 

 of fresh particles brought to it by the arteries, 

 while others are carried away by the absorbents, 

 and gradually acquiring the form which is to 

 qualify it for the performance of its proper 

 office in this vast and complicated system. 



his *' Anatomie comparee du cerveau," p. 25 ; and also his se- 

 veral memoirs in the " Annales des Sciences Naturelles," vols. xi. 

 xii. xvi. and xxi. 



An excellent summary of the principal facts relating to the 

 developement of the embryo is given by Mr. Herbert Mayo, in 

 the third edition of his " Outlines of Human Physiology." 



