The Edinburgh New Philosophical Journal. 257 



and red colours, with all their variations, may he found in roses with- 

 out distinction, and yet no new species be created. All the shades 

 between white and red, form in this case, then, a natural series, the 

 members of which may be substituted for each other without changing 

 the nature of the rose. 



" Professor Mohs has made a very successful application of these 

 principles to mineralogy, or, to speak more properly, these ideas of 

 natural characters and the series they constitute, owe their origin to 

 this distinguished philosopher. The creation of the systems of crystal- 

 lization, such, for example, as the tessular, rhomboidal, pyramidal 

 systems, &c, gave birth to as many natural series, containing a multi- 

 tude of members, all of which may be substituted for each other, but 

 which are in themselves essentially separated, and cannot be confound- 

 ed. Thus it is of little importance, for the determination of a species, 

 whether the mineral be crystallized under the form of a cube, or any 

 other derived from that; but never can it present, for example, a 

 pyramid form, for there is no transition between a cube and a pyramid. 

 " It is only characters, then, which distinguish series, and which admit 

 of no transition, that can authorize us to establish distinctions between 

 beings, and create new species. Whenever there is a passage between 

 the characters of a new individual and those of one previously known, 

 we cannot make a real division. Unhappily the neglect, or perhaps 

 the ignorance, of these principles, has led many naturalists to create 

 a multitude of species founded on distinctions quite futile, and (if I 

 may be pardoned the expression) altogether foolish, producing an 

 incumbrance of new species sufficient to cause disgust for the study 

 of natural history. 



" There is only one way to remedy this abuse, that is to study true 

 natural characters, to observe attentively the series they constitute, 

 and to make a rigorous application of them in the classification of 

 animals. Scales appear to us to offer one of these natural characters 

 for the classification of fishes. The intimate connection subsisting 

 between the tegumentary appendages and the organization of the 

 animal, of which we have already spoken in the former chapter, affords 

 a very strong argument in favour of our opinion. We do not wish 

 to rest our case on the reason that, because fishes can live when depri- 

 ved of their fins, but not when deprived of their scales, it therefore 

 follows that scales have a greater physiological value than fins. Such 

 an argument would be too imperfect and inconclusive. 



" The physiological importance of scales has but little to do with our 

 present purpose; we only want to know, in this case, whether they 

 can afford a distinctive character between different individuals. Now, 



