INTRODUCTORY LECTLRE. 6 



teristic modifications of the Human frame ; and then only can we be 

 said to know properly our own structure, and, from Anthropo- 

 tomists, to become Anatomists in the true sense of the word. 



As such we begin to feel ourselves in possession of an instrument 

 which can be brought to operate successfully in the solution of 

 deep and difficult problems of more general interest in the common- 

 wealth of knowledge, and which renders us indispensable auxiliaries 

 in the advancement of Sciences which might at first appear to have 

 but a remote relationship with Anatomy, I need not expatiate on 

 the light which Anatomy lends to the Zoologist, in threading the in- 

 tricate mazes of the natural affinities of animals : it is, by universal 

 consent, admitted to be the essential basis of a sound system of classi- 

 fication. I need not dwell on the importance of the Comparative Ana- 

 tomy of the minute and low organised Invertebrata in establishing 

 true theories, and eradicating false notions, of the origin of living 

 species ; of which different hypothetical secondary causes have been 

 from time to time offered for the acceptance or speculation of the 

 thinking public. 



But I would allude to' the power which the appreciation of the co- 

 relations and interdependencies of the several parts of each organic 

 machine gives us to interpret the natui'e of the whole from the ob- 

 servation of a part. 



By this principle its discoverer, the immortal Cdvier, and his 

 successors in this application of Anatomy, have been enabled to re- 

 store and reconstruct many species that have been blotted out of the 

 book of life. By this we determine from fossil bones or fragments, 

 submitted to us by the Geologist, the species which are charac- 

 teristic of different strata. By physiological deductions we can prove 

 that such species, now extinct, have lived and died, generation after 

 generation, through the period when those additions were made to 

 the earth's crust wliich their remains characterise. 



Thus, and thus only, can we obtain a clear idea of the lapse of 

 time in which tliese formations have taken place. The order of 

 superposition of strata indicates, indeed, their successive formation, 

 but the determination of their organic remains proves that each 

 formation was gradual and progressive. 



One of the results of this application of Anatomy has been no less 

 than the discovery of the law of succession of animal life on this 

 planet, or the determination of the relative periods at which the dif- 

 ferent classes were successively called into being. 



Another result may be expected, and is in progress, as a corollary 

 of the preceding, viz. the determination of the true Chi-onology of 

 the Earth. 



B 2 



