ll PREFACE. 
with the present taste, than would be amply sufficient to build one up anew from a new foundation upon the 
same site. The materials of the old fabric may be sound enough to serve in a new design, but the erection 
of this latter requires the dismemberment .of the former, and the granite facts which outlasted the century 
may, by re-adjustment in a more modern style of architecture, be made to stand out another age just as 
well as if they had been hewn from the quarry only yesterday. Comparative Osteology is an ancient 
superstructure promising to be raised upon the facts of skeleton analogies, and according to the law of unity 
in variety ; but the process of developing the complete design of this edifice has been carried on so 
slowly, that the materials have grown old, and have put on an antique facing before any one has as 
yet seen or understood for what general fabricated whole they have been piled together. 
The cause of this slow process of formation may perhaps arise from the circumstance, that many 
architects, each with a design of his own, and various to that of all the rest, have been employed 
upon the construction of an entire fabric which was never yet, in any instance beside the present one, 
completed off-hand on this very account. The unity of an entiré must be the work of one agent, and 
with whom all other assistants must work conformably. Nature is seen to operate upon this principle in all 
instances, and if we would ascertain clearly from what cause the mind so often overreaches itself and fails in 
the attainment of its purpose, we must compare the mental act with the natural. operation, by which 
. contrast the proof becomes evident, that as it is the law of Nature to fashion the unity of a whole 
by the subordination of its parts, so in opposition to this fixed rule it becomes impossible for the 
mind to know the unity of truth by giving way to ideas which distract contrariwise, and as it were all 
equally prominent in salient angles, When every individual interest is contending for supremacy and 
‘the first place, the common interest is then annihilated. The unity of the whole is broken when every 
part forsakes its proper locality, and for which. alone it is a fitting element. As every arch is. 
constructed of its subordinate parts, and is completed by the key-stone ; as every state holds together 
| lastingly by the harmonious union of ‘its people, subservient to one chief magistrate ; as enchained gradation 
is the principle of all things; and as all’ things which serve for a whole design are equally fitting 
and useful to that design ;- so does it appear that the principle of unity governs Nature in all her 
states; and as it is so, then the best test of truth in any science is in so far as this developes the 
idea of unity and the harmony of an entire. | . . 
Analogy is that principle whereby relationary facts cleave together, and body forth the whole 
structural design of unity. Analogy is the pabulum of Science, and to it Science owes its vital increase, 
because it is a something which Science may assimilate to her own person, and work upon after having 
digested it. Comparative Osteology, the unity in variety, and the law of formation, being the subject 
at present treated of, I shall-state briefly the plan and order in which I have directed my studies, and how 
far the opinion here entertained of this law of development has grown upon the soil and basis of - 
analogous facts. . 
In the schools we are taught the precept that the progress of Science must be according to Nature 
and her phenomena, and that every spoken or written opinion concerning the natura which shall seem 
a mystery in few or many respects cannot have that mystery cleared away from it by any other 
mode except by holding that opinion in comparison with Nature, and proving where it agrees or 
disagrees with her own person. For, assuming that every opinion whatever is upheld by an actual 
conviction of its truth and rationality, one has as good a right to stand by its cause as another ; and 
however erroneous or truthful either may be in itself, there appears no other means of judging unless 
that of submitting both to the standard reality of Nature, before whose tribunal all opinions must 
yield if they be not according to her evidence and proofs. 
