8 INTRODUCTION. 
exist, or where the analogies commenced to arise.* To which the answer may be returned, that if unity be 
the integer or archetype, and variety be the proportionals of the same, then as proportioning, or the 
subtraction of quantity from an archetype, is creative of variety, it becomes impossible to draw a defined line 
of separation between such diversities and such analogies. The difference between any two skeleton 
quantities may be infinitesimal and inappreciable, incomparable, less than any assignable quantity, and 
therefore accounted as nothing. Thus may this pursuit after the vanishing point of difference introduce 
into comparative osteology the Differential and Integral calculus, or the doctrine of fluxions, which for 
obvious reasons we shall not adopt in these pages, further than may be required. It will be sufficient 
for anatomy that we clearly understand how the subtraction of quantity from one of two equals or analogues 
is that law which creates variety or difference as to quantity, and that the parts which remain for minus still 
hold their counterparts in plus. 
The anatomist had now begun to perceive analogies to exist in other parts of the animal figures 
beside those of the central spinal chain of the vertebral bones. The unity of type was now observable in 
all scapulary and pelvic organs, despite the manifold examples of | metamorphosis to which these seemed 
- subjected ; so also were the vertebral bones traced through that transition development which planned, 
from out of certain members of them, the animal. skull; so also were the modifications of the thoracic 
apparatus noticed in a surprise ; and when the skeleton figures of all classes were held in comparison with 
each other, that marvellous circumstance of their special plans of different development instanced in the 
relation of skull to thorax, thorax to locomotive organs, the disappearance of one part, the reappearance of 
another, the apparent new creations of structures in many animal forms, and the lessening of the so-called 
normal type of others, nay the positive fact now and then appearing which proved that the human skeleton. 
figure itself was a structure which increased by certain creations of superadded products, or decreased 
from the normal type in many examples,—these were the facts which rendered the phrase “ uniformity” as 
one of doubtful meaning,+ and to which mystery must for ever attach so long as it shall be applied to 
characterise equality amongst figures which are in fact the proportionals or variable quantities of an integer. 
All these possible variations of plan happening, whilst the uniformity of type, in greater or lesser degree, 
nevertheless prevailed and was discoverable through all, such ae the facts which could not fail to have 
awakened the interest to the inquiry whether it be the unity which suffers modifications to the creations 
* Tt has been the main object with naturalists of all ages to found a perfect classification of the Animal Kingdom, that is to 
ah a classification based on the exact and complete knowledge of the resemblances and differences between all beings of the animal 
scale, and of determining with precision and clearness the relations and analogies of anatomical structure. The difficulty of this 
subject is sufficiently proved, from the fact, that naturalists have occupied themselves, to very different results. Classifications are 
very numerous, and often based upon opposite principles. LHven the classification of Cuvier himself has not completely satisfied 
the higher philosophy of the universal analogists. And it is most true that all progress in the science of comparison tends to the 
goal of unity rather than to that ideal place which classifiers have supposed to be situated between uniformity and difformity. 
+ Cuvier, while examining’ the principle of Geoffroy’s “Unity of Organic Composition,” expresses himself as follows :—< Si 
vous prenez les mots dans leur acceptation la plus rigoureuse, vous ne pourrez dire qu’il y a unité de composition dans deux genres 
d’animanx, qu’ autant qu’ils sont composés des mémes organes. Par unité vous n’entendez done pas identité; mais, donnant & ce mot 
un sens différent de celui qu’on devrait naturellement lui supposer, vous vous en servez pour signifier ressemblance, analogie. Parlez- 
vous d’identité absolue ou simplement d’analogies, de ressemblances?”” ‘‘ Je n’ai,’’ answers Geoffroy, “ jamais rien entendu au-dela 
de ce que ces derniers mots expriment.’’—See Les Temps et Le National of March, 1830. Resumé des doctrines relatives a la 
ressemblance philosophique des étres. 
