LINNEAN SOCIETY OF LONDON, 



they will be admitted by many as a provisional hypothesis, to be 

 further tested, and to be discarded only when a more plausible one 

 shall be brought forward. 



In conclusion, I cannot but express my belief that it will be gene- 

 rally admitted that Mr. Darwin has in this work most satisfactorily 

 laid before us the first important instalment of that great repertory 

 of facts from which his celebrated theory has been deduced ; and we 

 can only look forward with the greater eagerness to the appearance 

 of that second portion (the variation of animals and plants in a 

 state of nature) the data of which are so numerous, and so varied in 

 their authenticity as well as in their signification, as to require all 

 Mr. Darwin's skill to test them, to methodize them, and to apply 

 them so as to enable us correctly to judge of the strength of his 

 conclusions. In the meantime, it is to be hoped that the spirit of 

 observation which his works have already called forth will be 

 carried out in the same direction by lovers of our science in all parts 

 of the world. Naturalists residing in countries where no new forms 

 are to be discovered, need not think that there is nothing for them 

 to do towards the advancement of biological science ; nor need they 

 be reduced to cataloguing individual or fleeting varieties in the form 

 of a leaf, or the hairs of its surface. Tracing out the history of a 

 plant or an insect from the first development of the egg to the final 

 extinction of its life, of the changes it undergoes in its internal 

 organization, of the vicissitudes of its life from external causes, local, 

 climatological, or social, of its relation to the surrounding organisms, 

 of the degree in which it is prejudicially or beneficially affected by 

 living beings of its own or of any other class, are now subjects of 

 inquiry much more important than difl^erences in external form. 

 But in every biological undertaking, whether it bo the monograph of 

 a group or the Fauna or Flora of a country, the exposition of a phy- 

 siological structure or of a phenomenon of life, the enunciation of a 

 new theory or the refutation of an old one, the periodical surveys I 

 have had to take of biological works have convinced me that there is 

 one true course to pursue : — first, to observe for one's self once and 

 again, and to test personally the observations of others ; secondly, to 

 collect, compare, and methodize all that has been published and 

 authenticated upon the group, the district, the organ, the phenome- 

 non, or the theory which is the subject of investigation ; and, 

 thirdly, and only after the first two processes have been exhaustively 

 carried out, to reduce the observations to a general treatise, and 

 speculate upon the conclusions to be drawn from them. And in this 



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