REMARKS ON THE FIGURES OF PLATE XXXIII. 8 
Neither does antero-posterior symmetry * characterise 
fig. D, for the dorsal face is minus, and the ventral face is 
plus; and hence there is every reason to conclude that 
asymmetry with respect to dorsum and venter, is the effect 
of the metamorphosing act of subtracting quantity. Now 
as every minus quantity which results by the subtraction 
from a plus sum must consequently refer to its original or 
whole quantity, in the same manner as a—6 refers to a+ 3, 
so shall we pursue the chainwork of this evidence of 
proportional degradation, and pace with it as by the 
guiding conduct of Ariadne’s thread, till from the lowest 
extreme of minus variation, we rise in gradual progression 
through increasing series to the opposite plus extreme, 
and find located there the whole quantity of absolute, 
uninterrupted, serial uniformity and symmetrical cast. 
The evidence of an infinite variation of anatomical facts 
has ever been repellent to the thinking mind of the philo- 
sophical interpreter. Generalisation and the abstract 
view, is that medium through which the philosophical 
anatomist has been compelled to regard the infinitude of 
special detail; the mental otium is marked by the idle 
detail of special variety ; + for there is nothing easier than 
to observe the fact that two or more quantities differ, 
whereas, on the contrary, the mental labour is characterised 
by the calculation as to how those quantities happen to be 
differenced, and in this consists the knowledge of a law. 
* “Man, however, has the parts of his body distinguished by the superior and inferior, the anterior and posterior, and the right and left. 
The right and left parts therefore, are nearly similar, and the same, except that the left parts are more imbecile ; but the posterior are dissimilar 
to the anterior.” —Aristotle, History of Animals. Book i., page 24. : 
+ “Il suffit pour cela, de parcourir les livres et les cabinets Whistoire naturelle, et d’admettre, comme caractéres spécifiques, toutes les 
différences, soit dans la grandeur, dans la forme, ou la couleur, et de chacune de ces différences quelque legere quelle soit, faire une espeéce nouvelle 
et séparée de toutes les autres ; mais, malheureusement, en augmentant ainsi trés-gratuitement le nombre nominal des espéces, on n’a fait 
qu’ augmenter en méme temps les difficultés de histoire naturelle, dont Vobscurité ne vient que de ces nuages répandus par une nomenclature 
arbitraire, souvent fausse, toujours particuliére, et qui ne satsit jamais Pensemble des caractéres ; tandis que c’est de la réunion de tous ces 
caractéres, et surtout de la différence ou de la ressemblance de la forme, de la. grandeur, de la couleur, et aussi de celles du naturel et des mecurs, 
qu’on doit conclure la diversité ou l’unité des espéces.”—Buffon, Oiseaux, tome i., page 71. 
{ “It is a remarkable circumstance how much labour it costs to establish with clearness a single fact of phikosophical anatomy. No one can 
form an idea of this unless by devoting himself to this kind of research. We may pass, not only hours or days, but even whole weeks before 
the skull of a fish, and contemplate with surprise this quarry of calcareous stalactites, without arriving at the knowledge of the why, the where, 
or the how.’—Oken, Jsés, 1818 ; pages 512, 5129. See also, Lehrbuch der Naturphilosophie, Jena, tom. iii., p. 61. 
