34 NATURAL HISTORY. [ciI. II. 



which appears to us to have been made by some au- 

 thors respecting the statement of Herold, of the op- 

 eration of a formative powe-r supposed to be pos- 

 sessed by the rete mucosum in effecting the various 

 developments of the insect, being convinced that 

 Dr. Herold merely intended to refer to the contin- 

 ued action of the living and growing principle im- 

 planted by Providence in this mucous network, and 

 not, as has been supposed, to a blind power pos- 

 sessed by it capable of acting without the superin- 

 tendence of nature or the Creator, and forming it- 

 self into various envelopes or organs. 



Hence, therefore, we do not consider the gradual 

 development of these organs to be less indicative 

 of the constant operation of the great Creator than 

 the growth of the chick in the egg, or of a plant from 

 seed ; neither do we think, after what has been ad- 

 vanced, that the theory of Herold will be deemed, 

 as it has hitherto been, a monstrous and untenable 

 one. Indeed, by construing the statemenc of his 

 theory (which we consider ourselves warranted in 

 doing) in the following manner, " the successive 

 skins of the caterpillar, the pupa-case, the future 

 butterfly and its parts and organs (except those of 

 sex), do not exist in the newborn caterpillar as vis- 

 ible germes, but are successively developed from the 

 rete mucosum," the objections which have been 

 made to it appear to vanish. 



Various authors have endeavoured to trace an 

 analogy between the growth of a butterfly through 

 its various stages and the development of the high- 

 er animals from the fcEtus until their arrival at full 

 growth ; but the result of these inquiries, as might 

 naturally be expected from the great difference be- 

 tween the construction of the animals, has hitherto 

 been contradictory. One class of naturalists view- 

 ing the extrication of the human foetus from its ex- 

 ternal envelope (chorion), and its subsequent con- 

 tinuance in the liquor amnii, have thought that the 



