12 THE THEtfcY tF EYtLTItN 



' catastrophic ' and ' creation ' theories do not afford 

 the most natural explanation of the history of life 

 lijDon the eaftnT" Another hypothesis was, however, 

 still impossTBIe^sD long as the absolute unchangeability 

 of the organisms was adhered to. 



Already, in Curier's lifetime for the first time, serious 

 attacks began tt lie made on the ' constancy ' theory 

 in trier to permit the possibility tf amatier significa- 

 tion being given t palsetnttltgical facts, and particu- 

 larly to establish an attmal collection between the 

 present and fossil organisms. Lamarck and Geoffrey 

 St. Hilaire had already, decades before the appearance 

 of d'*rbigny's ' Cours elementaire/ put forward theories 

 on quite new and unheard-of lines. But their ideas 

 found no proper response among their contemporaries. 

 It was reserved for Charles Darwin to obtain for the 

 new doctrine a general acceptance : in what sense that 

 should be properly understood we shall speedily see. 



All agreed that the living and fossil animal and 

 plant forms are connected genetically, i.e. by descent. 

 Thus the many new creations became superfluous. 

 These were, indeed, only insisted upon because that 

 connection was denied. The difference established 

 by palaeontology of offspring between themselves 

 and from their ancestors finds its explanation in the 

 variability of the organisms, which, in the sharpest 

 contradiction to the ' constancy theory/ became re- 

 garded as a fundamental quality of all living things. 

 Since palaeontology furthermore presented some evi- 

 dence that the difference of form of the progeny was 



