of Local Farieliey. 67 



on these questiahs, complicated and difficult, it is true, but still accessible 

 to our reason and observation. TlierC; differences of a less decided kind 

 arc established, under the action of real and active, but less powerful, 

 causes of diversity ; there, the influence of local circumstances is often 

 shewn in a very evident manner, which, leaving all the essential condi- 

 tions of the common ground-work untouched, still make it undergo a 

 slight alteration. In other words, it is there that types differing slightly 

 from each other are established, which all zoologists designate by the 

 name of local varieties ; thus unanimously recognising in application, 

 and, if I make use of the expression, in practice, that powerful modifica- 

 tion of exterior agents, which so great a number of them deny more or 

 less completely in their theories. These varieties of locality, tending to 

 establish the passage of one species into anotJier, have hitherto been 

 scarcely any thing else, in natural history, than a subject of serious diffi- 

 culties and continual doubts ; and such will continue to be the case as 

 long as the distinction of beings, and the precise knowledge of differen- 

 ces, shall be the principal and almost the only objects which zoologists 

 propose to themselves.' Now, on the contrary, when the progress of 

 science has reached such a point (and we may certainly say that we have 

 almost reached it), that there will not only be a desire to note, but also 

 to appreciate differences, not only to classify species, but to explain their 

 formation, the study oi local varieties, those demi-species, as they may be 

 called, will become one of the favourite subjects of investigation with 

 zoologists, since it will be one of the most fruitful in definite results, re- 

 sults which will have an immediate application to natural philosophy. 



" Another kind of interest also attaches itself, in some particular cases, 

 to the comparative study of beings belonging to regions not widely sepa- 

 rated. Certain countries, placed between two zones very different in 

 climate, and intermediate to each other by their physical conditions, 

 such as situation, ought, according to the particular circumstances of 

 their topographical disposition, to present us with a distinct passage be- 

 tween two orders of things, or, according to an expression already admit- 

 ted into science, and previously employed in this article, between two 

 different creations. These are truly what may be called, to borrow an 

 expression from another brancVi of natural history which best conveys the 

 idea, transition countries ; and if the whole of their productions, deprived 

 of a striking and well marked special character, but, on the contrary, shar- 

 ing at the same time the conditions of neighbouring regions, do not call 

 the attention by the appearance of its contrasts, to those natural opposi- 

 tions which speak so loudly to the im.'igination, the study maj" at least 

 reveal to the observer a multitude of those secret relations, concealed 

 analogies, and fruitful inductions, which contemplative minds delight to 

 discover under the thick veil which conceals them from the vulgar eye." 



