in the " Diclionnaire des Sciences Naturelles.'' 103 



as to their qualities, the groups into which they are assembled 

 might be considered equally definite. The value of these groups 

 •would be invariably the same, and the names chosen to represent 

 them might be set down as fixed, and at all times proper for the 

 purposes of communication already stated. S/r/iiu might thus 

 always continue Semia, and an original PsUtaais^ according to 

 the views of iM. Desmarest, be a t*sittacus to the end of time. 

 But there is this peculiarity in Natural History, particularly in 

 its earlier stages beyond which it can scarcely even now be con- 

 sidered as having advanced, that the number of its subjects can be 

 reduced to no limits. Every day's experience proves that their 

 increase eludes all our etForts to circumscribe them. It conse- 

 quently happens that the original groups, which at first were 

 proximate in our ideas to species, cease to continue so ; and the 

 mind seizes upon intervening characters of distinction by which it 

 is enabled to reduce the increasing subjects within a comprehen- 

 sible compass. The limits of species may perhaps, be considered 

 capable of being defined, although I must confess I think even 

 this point problematical : but until our knowledge of nature 

 becomes perfect, — a period little to be expected, — the next proxi- 

 mate groups to species must ever be subject to variation. 



A single instance will illustrate this remark, as well as point out 

 the process by which the mind endeavours to proportion its groups 

 to the increasing number of the subjects brought before it. Lin- 

 naeus, in his attempts to reduce the Coleopterous Insects into 

 order, observed several species among them which bore a similitude 

 to each other in their general structure, in having apparently six 

 palpi, and in their antenna' being filiform. Ke characterized this 

 group accordingly ; and as it was the proximate group to species 

 he called it a genus, and distinguished it by the name of Carabus, 

 The number of species known to him amounted to forty-two. 

 Small as was this number, in comparison to that known in our 

 days, it appears that he considered it too extensive for a single 

 group, and he accordingly made an artificial but still a convenient 

 subdivision in it according to size; separating the species into 

 7n(ijores and minores. As the subject began to be more closely 

 investigated, the discovered species became excessively numer- 



