MONSTERS IN ANIMALS. 243 



posed on the external surface of the vegetable ; in effect, similar to the 

 crystal ; so that the vegetable works up itself. Animal growth is so 

 far similar in being [seated in] matter of its own, formed so by the 

 animal itself, and disposed of by it : not by accretion as in the crystal ; 

 nor by disposing its own materials on the outside as in the vegetable ; 

 but by an interstitial deposit of its own assimilated matter, by which 

 the whole is expanded. 



An animal, like a vegetable, has a portion of its own matter so 

 arranged as to have the power of growth, and the first principle of 

 monstrosity may have taken place in this first arrangement ; and what 

 makes this very probable is, that most of the monsters are formed as 

 early as we can observe any formation. However, this is not always 

 the case ; therefore we have monsters before birth and after ; which I 

 shall consider further. 



Monsters before Birth. 



The first class of monsters in animals are those that are born so. Now 

 let us inquire in what respect is an animal, some time before birth, 

 similar to a vegetable, or to the parts of animals which have the power 

 of regeneration after birth. We are to consider, first, that the life of an 

 animal, before birth, is very different from what it is after. This differ- 

 ence in the principle of life [before birth] comes much nearer to vege- 

 tation, and most probably the further back we go, this similitude is the 

 stronger. I fancy in this inquiry we must go as far back as the first 

 formation of the animal, when the matter is moving into different forms, 

 similar to the formation of a new layer or a new shoot in a vegetable ; 

 for in neither animal nor vegetable are the parts formed at once. A 

 vegetable is, at all times, similar to the first formation of an animal, or 

 to the new formation in a lizard's tail. These [i. e. the growing branch 

 or regenerated tail] meeting with obstructions to their [proper] forms 

 readily admit of duplication ; but I believe seldom of more. 



That it [the principle of monstrosity in animals] is as early as the 

 first formation, appears from the supernumerary part being almost 

 always placed with the natural or corresponding one ; viz. two heads 

 are always on the shoulders; four legs are always placed at the lower 

 part of the belly ; a supernumerary finger or toe is on the hand and 

 foot; &c*. Even in the hair, &c. the monstrosity is similar to the 

 original 1 . 



* This, however, is not universally the case, as I have a young duck with a foot 

 growing out of its head. [Hunt. Prep. Series of Monsters, No. 31.] 



1 [See also the subsequent 'loose note,' p. 251, for further illustration of tins im- 

 portant principle.] 



E2 



