THE VEGETABLE AND ANIMAL KINGDOMS. 135 



rendered permanent by equally mysterious agency." It is 

 more than probable that the greater number of what may be 

 called the domesticated plants, are unsuspected variations of 

 others, which, growing wild, are recognised as different species. 

 One noted instance of such transition has been detected within 

 the last few years, in our different kinds of cabbage, savoy, 

 brocoli, and cauliflower. They are all common descendants 

 of a plant which is sometimes found growing wild upon our 

 sea-shores, the brassica oleracea a transition which no one 

 can appreciate till he has compared the tough slender stem 

 and small glaucous leaf of the original, with the stout fleshy 

 stem and large succulent leaves, sometimes gathered into a 

 heart several feet in circumference, which he will find in the 

 most familiar of the cabbages. 



What respect, it may be asked, can we attach to the doc- 

 trine of intransibility of species, when we find its adherents 

 wrong in so many instances ? Admit their explanation, that 

 a mere mistake has been made in calling that species which 

 was only variety, what guarantee can we have for the fixity 

 of any so-called species, when it has given way in such in- 

 stances ? What t* species, if it cannot be fixed upon such 

 a vast assemblage as the Thallogens, or even the progeny 

 of the Telephora sulphurea ? Apart from all theorising 

 about the absolute characters of species, do not these facts 

 show a transibility and intercommunion of forms totally at 

 variance with those general opinions as to fixity which now 

 reign in the scientific world ? 



In the animal kingdom, we have fewer illustrations of 

 modifiability or transition ; but they tend to exactly the same 

 effect. We shall here pass over the succession of forms 

 which appears in common infusions. Neither shall we enter 

 into the particulars of a late curious investigation by a 

 Danish naturalist, which results in showing alternative forms 

 in the succession of certain animals low in the scale, in- 

 cluding the medusa; that is, as it were, A giving birth 

 to B, B to C, and C to A again. C* 5 ) Such matters are as yet 

 obscure, however highly they may promise in time to illus- 

 trate this question. Let us rather look to departments of this 



