CONCLUDING REMARKS. 199 
attending the investigation of these two groups, as well 
as that of the Trochilide, which is this; — that however 
naturalists may differ about the primary nature of other 
birds, they will be unanimous respecting these; a par- 
rot or a woodpecker cannot belong to any other groups 
than their own: Nature herself has separated and 
characterised them from all others; so that the investi- 
gator knows at once the extent of the group he has to 
deal with, and he has only to make out its internal 
relations. In short, I consider the Piciane to be so 
perfect a circle, that I have been accustomed to view 
it, in all doubts and misgivings regarding others, as 
that upon which I could fall back, as upon a strong 
and impregnable hold, for demonstrating those first prin- 
ciples of the natural system I have, perhaps, too boldly 
announced. In regard to nearly all others, I may em- 
ploy the words of two eminent writers who have had to 
contend with the same difficulties in the same line of 
inquiry. ‘‘ When we cannot represent Nature as she 
is, we must endeavour to represent her as she appears 
to be; for if we suspend our observations in appre- 
hension of committing an error, we shall soon cease to 
_ represent her at all.” * 
* MM. Horsfield and Vigors; Linn. Trans. xv. 328. 
