VI. 
alteration termed “accidental varieties/’ the precise causes 
of which however are as yet unknown. These variations 
serve at times to illustrate the nature of those laws which 
affect organization ; again, the same, and all other local 
circumstances are apt to produce variations of habit, which 
tends forcibly to shew that considerable latitude has been 
given to animals in the exercise of what are termed their 
instinctive actions. I shall endeavour to shew this in the 
portions of the work which treat respectively of these 
subjects. The alterations effected in the face of a given 
locality by the ameliorating powers of agriculture, horti¬ 
culture, planting, &c. together with the hostile operations 
of man on the original state of Nature, conspire to produce 
differences in the geography, numbers, habits and struc¬ 
ture of plants and animals ; and thus these interferences 
serve to derange the general polity of nature, or the mutual 
dependance of the three natural kingdoms, and, by shewing 
us the detrimental consequences to organic nature, enable 
us in some degree to comprehend the laws, which kept 
the members of the series in their just and natural 
connexions. 
These then are a few instances taken quite at random, 
to prove that a knowledge of the phenomena displayed by 
* 
the Natural History of localities, is essential to a due 
acquaintance with the laws which control the existences, 
the oeconomies,the instincts, the structures, the geographi¬ 
cal positions, the natural classifications, and the mutual 
relations, and connexions of plants, and animals. 
In the last place I observe, that the geologies of 
localities generally present differences worthy of note, 
and render it highly probable that though some few 
