tliirty-six, the Badger tlilrtv, the Dog twenty- 
six, Man twenty-four, &:c. This difFerencc 
in the struclure of the Sloth indicates a greater 
distance between these two sj^ecics, than, be- 
tween the Dog and Cat, which have both the 
same number of ribs: for external diflerenccs 
are nothing, when compared to those which 
are internal ; the former may be regarded as 
causes, and the latter as effe6ls only. Tlie 
interior frame of animated beings is the foun- 
dation of Nature's plan; it is the constituent 
form, and the origin of all figure; but the ex- 
ternal parts are only the surface or drapery. 
How often have we not fomid, in the course 
of our comparative examination of animals,, 
that a very different external appearance co- 
vered internal parts pcrfecllv similar; and that* 
on the contrary, the slightest internal dis- 
tindlion produced great external differences, 
and changed the natural dispositions, powers, 
and qualities, of the animal ! How manv 
animalsarc armed, covered, and adorned, with 
excrescent parts, whose external stru£lure cor- 
responds exadlly with others which are totally 
deprived of such ap})endages ! But this,'* adds 
Buffbn, is not a place for such nice disqui- 
quisitions * 
