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from their afflictions and witlistood their vicissitudes, as similar 

 grades of animals do now; bnt the abrupt appearance of a distinct 

 genus, in a given geological age, and its coniinement to a limited 

 geogvapliit-al area, and then its absolute extinction when it seems to 

 have reached its largest size and most (complete development, must 

 be the rOKult of some law or combination of laws which we not only 

 do Hot understand, but of which we have no rational conception. 



The fo.ssils are tlie farts and the evidence in pahijontology, antl 

 they have been collected in detached and remote places and stored 

 in difl'erent states. From having observed a very limited number of 

 these facts some authors have built cloudy systems ami made use- 

 less siJeculations that are mere rubbish in the way of progress. The 

 fossils are the indexes of nature: they must be observed with the 

 eye. and from their appearance only can we become acquainted with 

 tlie anatomy or hard jjarts of the animals. Until we are thoroughlj' 

 accjuainted with the anatomy of an animal, we are unprepared to 

 discuss its physiology. Physiology is the word used by the medical 

 men to express tlie .science which vinfokls the nature of life, the 

 etymology and original acceiJtation of which means the doctrine of 

 nature, but Treviranus. a (Tcrman author, at a comparatively recent 

 (late, proposed the term "Ijiology" for science of life instead of phy- 

 siology, and naturalists who are not medical men use the word 

 ■"biology" exclusively, and medical men generally retain the older 

 name "physiology" to express one and the same thing. The biology 

 is inseparable from the anatomy. The liiological functions are 

 inaiiifi'sted as the anatomical parts are developed and eomiileted; 

 they are modified with the afflictions of the anatomy; they decline 

 and decay with it, and the biological functions cease when the softer 

 anatomical [)arts are destroyed. 



It was not uncommon for naturalists in the last century to arrange, 

 from a few specimens in a museum, what they supposed repre- 

 sented the aiumal kingdom, in a successive series of development 

 governed by the external appearances. They followed the chain, as 

 they supposeil, link after link, without a break, innocent of the fact 

 that the internal comparative anatomy, when examined, would break 

 the chain into fragments and wholly destroy the fancy of the gradual 

 ascension and j)rogression. We think we have seen in recent 

 paheontologieal productions the arrangement of fossil shells, in suc- 

 cessive series, from species to species, through different geological 



