404 



kxo\\li:dge. 



October, 1912. 



Sii' Joscpli, and preseiitiiiK to liiiii the Darwin-Wallace Medal, 

 have been improved. He said: "The incalculable benefit 

 that your constant friendship, .idvice, and alliance were to 

 Mr. Darwin himself, is summed up in his own words, used in 

 1864 : ' You have represented for many years the whole great 

 public to me.' " The President then added : " Of all men 

 liviuK it is to you more than to any other that the great 

 generalisation of Darwin and Wallace owes its triumph." 



The very last appearance of Hooker at any large public 

 gathering of biologists was at the centenary of Darwin's 

 birth, celebrated at Cambridge, in 1909. None who were 

 there will forget the tall figure of the veteran, aged, but 

 still vigorous, with vivacity in every feature. How gladly 

 he accepted the congratulations of his many friends, and 

 how heartily he rejoiced over the full acceptance of the theory 

 he had himself done so much to promote. The end came only 

 two years later, in December last. Many will have wished 

 that the great group of the protagonists of Evolution, Darwin, 

 Lyell, and Hooker, should have found their final resting-place 

 together in Westminster Abbey. But this was not to be. 

 Personal and family ties held him closer to Kew. And he 

 lies there in classic ground beside his father. 



Having thus sketched the intimate relations which subsisted 

 between Hooker and Darwin, it remains to appraise his own 

 positive contributions to Philosophical Biology. He himself, 

 in his Address as President of the British Association at 

 Norwich in 1868, gives an insight into his early attitude in the 

 enquiry into biological questions. " Having myself," he says. 

 " been a student of Moral Philosophy in a Northern University, 

 I entered on my scientific career full of hopes that Metaphysics 

 would prove a useful mentor, if not a guide in science. I soon 

 found, however, that it availed me nothing, and I long ago 

 arrived at the conclusion so well put by Agassiz, when he says : 

 ' We trust that the timeisnot distant when it will be universally 

 understood that the battle of the evidences will have to be 

 fought on the field of Physical Science, and not on that of the 

 Metaphysical." This was the difficult lesson of the period 

 when Evolution was born. Hooker learned the lesson early. 

 He cleared his mental outlook from all preconceptions, and 

 worked down to the bed-rock of objective fact. Thus he was 

 free to use his vast and detailed knowledge in advancing, 

 along the lines of induction alone, towards sound generalisa- 

 tions. These had their very close relation to questions of the 

 mutability of species. The subject was approached by him 

 through the study of geographical distribution, in which, as we 

 have seen, he had at an early age become the leading 

 authority. 



The fame of Sir Joseph Hooker as a philosophical 

 biologist rests upon a masterly series of Essays and 

 Addresses. The chief of these were "The Introductory 

 Essay to the Flora Tasmaniae, dealing with the Antarctic 

 Flora as a whole " ; " The Essay on the Distribution of .'Xrctic 

 Plants," published in 1862; "The Discourse on Insular 

 Floras," in 1866; The Presidential Address to the British 

 Association at Norwich in 1868; his .-Address at York, in 

 1881, on Geographical Distribution; and finally, "The Essay 

 on the Vegetation of India," published in 1904. None of 

 these were mere inspirations of the moment. They were the 

 outcome of arduous journeys to observe and to collect, and 

 subsequently of careful analysis of the specimens and of the 

 facts. The dates of publication bear this out. " The Essay 

 on the Antarctic Flora " appeared about twenty years after 

 the completion of the voyage. " The Essay on the Vegetation 

 of India was not published till more than half-a-century after 

 Hooker first set foot in India. It is upon such foundations 

 that Hooker's reputation as a great constructive thinker is 

 based. 



The first-named of these essays will probably be estimated 

 as the most notable of them all in the history of Science. It 

 was completed in November. 1859, barely a year after the 

 joint communications of Darwin and Wall.ice to the Linnaean 

 Society, and before the " Origin of Species " had appeared. 

 It was to this Essay that Darwin referred, when he wrote that 

 " Hooker has come round, and will publish his belief soon." 

 But this publication of his belief was not merely an echo of 



assent of Darwin's own opinions. It was a reasoned state- 

 ment, advanced upon the basis of his " own self -thought," and 

 his own wide systematic and geographical experience. From 

 these sources he drew for himself support for the " hypothesis 

 that species are derivative, and mutable." He points out 

 how the natural history of Australia seemed specially suited 

 to test such a theory, on account of the comparative 

 uniformity of the physical features being accompanied by 

 a great variety in its flora, and the peculiarity of both its 

 fauna and flora, as compared with other countries. After 

 the test had been made, on the basis of study of some 

 8000 species, their characters, their spread, and their relations 

 to other lands, he concludes decisively in favour of mutabiUty 

 and a doctrine of progression. 



How highly this Essay was esteemed by his contemporaries 

 is shown by the expressions of Lyell and of Darwin. The 

 former writes: "I have just finished the reading of your 

 splendid Essay on the Origin of Species, as illustrated by 

 your wide botanical experience, and think it goes far to raise 

 the variety-making hypothesis to the rank of a theory, as 

 accounting for the manner in which new species enter the 

 world." Darwin wrote: "'I have finished your Essay. To 

 my judgment it is by far the grandest and most interesting 

 essay on subjects of the nature discussed I have ever read." 



But besides its historical interest in relation to the species 

 iiuestion. the Essay contained what w^as up to its time the 

 most scientific treatment of a large area froEU the point of 

 view of the plant-geographer. He found that the .Antarctic. 

 like the .4rctic, Flora is very uniform round the Globe. The 

 same species in many cases occur on every island, though 

 thousands of miles of ocean may intervene. Many of these 

 species reappear on the mountains of Southern Chili, ."Vustralia, 

 Tasmania, and New Zealand. The Southern Temperate Floras, 

 on the other hand, of South .-Vmerica. South Africa, -AustraUa. 

 and New Zealand differ more among themselves than do the 

 Florasof Europe.Northern.\siaand North .\merica. To explain 

 these facts he suggested the probable former existence, during 

 a warmer period than the present, of a centre of creation of 

 new species in the Southern Ocean, in the form of either a 

 continent or an archipelago, from which the .Intarctic Flora 

 radiated. This hypothesis has since been held open to doubt. 

 But the fact that it was suggested shows the broad view which 

 he was prepared to take of the problem before him. His 

 method was essentially that which is now styled " Ecological." 

 Many hold this to be a new phase of botanical enquiry, 

 introduced by Professor Warming in 1895. No one will deny 

 the value of the increased precision which he then brought 

 into such studies. But in point of fact it was ecology on the 

 grand scale that Sir Joseph Hooker practised in the Antarctic 

 in 1840. Moreover, it was pursued, not in regions of old 

 civilisation, but in lands where Nature held her sway untouched 

 by the hand of man. 



This Essay on the F'lora of the Antarctic was the prototype 

 of the great series. Sir Joseph examined the Arctic Flora 

 from similar points of view. He explained the circumpolar 

 uniformity which it shows, and the prevalence of Scandinavian 

 types, together with the peculiarly limited nature of the Flora 

 of the southward peninsula of Greenland. He extended his 

 entjuiries to oceanic islands. He pointed out that the condi- 

 tions which dictated circumpolar distribution are absent from 

 them ; but that other conditions exist in them which .iccouut 

 for the strange features which their vegetation shows. He 

 extended the application of such methods to the Himalaya 

 and to Central .Asia. He joined with Asa Gray in like 

 enquiries in North America. The latter had already given a 

 scientific explanation of the surprising fact that the plants of 

 the I'^astern States resemble more nearly those of China than 

 do those of the Pacific Slope. In resolving these and other 

 problems it was not only the vegetation itself that was 

 studied. The changes of climate in geological time, and 

 of the earth's crust as demonstrated by geologists, formed 

 part of the basis on which he worked. For it is facts 

 such as these which have determined the migration of 

 floras. And migration, as well as mutability of species, 

 entered into most of his speculations. The essays of 



