LINNEAN SOCIETY OF LO>"J)ON. 25 



PRESIDENTIAL ADDRESS, 1920. 



During his various tnivels, especially in Oeland, Gothland, and 

 Scania, Liniiceus became niucli intereisted in tlie ])etriHed remains 

 of animals and plants which he and his students collected from 

 the stratified rocks. He made careful observations on their mode 

 of occurreuce, compared his results with those already published 

 by naturalists in other countries, and eventually, in the 12th 

 editiou of his ' Systema Naturae,' devoted an important section 

 to the arrangement and interpretation of the numerous " jjetri- 

 factions " by that time known. He quoted with approval the 

 Italian Eamazziui's remark that the layers of rock should be 

 considered as representing a succession of ages rather than as 

 "the tumultuous jumble of the general deluge." In the quaint 

 words of Dr. William Turton's translation, he concluded : — " The 

 intelligent investigator will not therefore straiten the limits of an 

 useful science, by disregarding the ancient inhabitants of the 

 globe, though unknown to modern naturalists." 



Since this wise and far-seeing observation of LinUcTeus in 1768, 

 " the ancient inhabitants of the globe" have indeed been much 

 " regarded," and it has become increasingly clear that they must 

 aKvavs be taken into account when the wider problems of life are 

 being considered. Not long after the foundation of the Ijinnean 

 Society towards the end of the eighteenth century, the succession 

 of extinct animals and plants was sufficiently understood to show 

 that there had been a gradual progression of hfe on the earth 

 from the lowest to the highest, and that the existing world was 

 only the consummation. When the details of the extinct forms 

 were studied, the differences between the past and the present 

 appeared to be even more marked. Still later, especially after the 

 work of Dai'win, when explorations and collections muUiplied, 

 many definite progressive and retrogressive sei'ies of animals were 

 recognised as they were traced through geological time. Even- 

 tnallv, during more recent years, curious parallel developments 

 have been noticed in many groups of different classes, which 

 suggest that certain changes are inevitable and are the successive 

 marks of immaturitj', dominance, and old age in each race. It is, 

 in fact, difficult to be sure of the real meaning of the characters 

 and distribution of any group of organisms as it exists to-day 

 without some knowledge of its ancestry in the past. 



Unfortunately, in most cases, this ancestry is unattainable ; 

 for organic remains are only preserved in rocks by accident, and 

 animals at any rate are rarely represented by more than their 

 skeletons. The vast majority of the most interesting genei'alised 

 tvpes of past ages must have lacked hard parts which could be 

 fossilised ; and even those which are represented by skeletons are 

 not easily interpreted unless they happen to have close allies 

 among existing life. 



