June 15, 1882] 



NA TURE 



147 



rather be said that plants acquire and display this power 

 only when it is of some advantage to them ; this being of 

 comparatively rare occurrence, as they are affixed to the 

 ground, and food is brought to them by the air and rain." 

 The diversity of the power of movement in plants natu- 

 rally engaged his attention, and the last but one of his 

 works — in some respects perhaps the most remarkable of 

 them — was devoted to showing that these could be re- 

 garded as derived from a single fundamental property. 

 " All the parts or organs of every plant while they con- 

 tinue to grow . . . are continually circumnutating." 

 Whether this masterly conception of the unity of what 

 has hitherto seemed a chaos of unrelated phenomena will 

 be sustained time alone will show. But no one can doubt 

 the importance of what Mr. Darwin has done in showing 

 that for the future the phenomena of plant movement can 

 and indeed must be studied from a single point of view. 



Along another line of work Mr. Darwin occupied him- 

 self with showing what aid could be given by the principle 

 of natural selection in explaining the extraordinary variety 

 of detail in plant morphology. The fact that cross-fer- 

 tilisation was an advantage, was the key with which, as 

 indicated in the pages of the "Origin of Species,'' the 

 bizarre complexities of orchid flowers could be unlocked. 

 The detailed facts were set out in a well-known work, and 

 the principle is now generally accepted with regard to 

 flowers generally. The work on insectivorous plants gave 

 the results of an exploration similar in its object and 

 bringing under one common physiological point of view a 

 variety of the most diverse and most remarkable modifica- 

 tions of leaf-form. 



In the beginning of this article the attempt has already 

 been made to do justice to the mark Mr. Darwin has 

 left on the modern study of geographical botany (and that 

 implies a corresponding influence on physio-palaeonto- 

 logy). To measure the influence which he has had on 

 any other branches of botany, it is sufficient to quote 

 again from the " Origin of Species" : — "The structure 

 of each part of each species, for whatever purpose used, 

 will be the sum of the many inherited changes, through 

 which that species has passed during its successive adap- 

 tations to changed habits and conditions of life." These 

 words may almost be said to be the key-note of Sachs's 

 well-known text-book, which is regarded as the most autho- 

 ritative modern exposition of the facts and principles of 

 plant-structure and function. And there is probably not 

 a botanical class-room or work-room in the civilised 

 world, where they are not the animating principle of both 

 instruction and research. 



Notwithstanding the extent and variety of his botanical 

 work, Mr. Darwin always disclaimed any right to be 

 regarded as a botanist. He turned his attention to plants 

 doubtless because they were convenient objects for study- 

 ing organic phenomena in their least complicated forms ; 

 and this point of view, which if one may use the expres- 

 sion without disrespect, had something of the amateur 

 about it, was in itself of the greatest importance. For, 

 from not being, till he took up any point, familiar with 

 the literature bearing on it, his mind was absolutely free 

 from any prepossession. He was never afraid of his facts 

 or of framing any hypothesis, however startling, which 

 seemed to explain them. However much weight he 

 attributed to inheritance as a factor in organic pheno- 



mena, tradition went for nothing in studying them. In 

 any one else such an attitude would have produced much 

 work that was crude and rash. But Mr. Darwin — if one 

 may venture on language which will strike no one who 

 had conversed with him as overstrained — seemed by 

 gentle persuasion to have penetrated the reserve of nature 

 which baffles smaller men. In other words, his long 

 experience had given him a kind of instinctive insight into 

 the method of attack of any biological problem, however 

 unfamiliar to him, and he rigidly controlled the fertility of 

 his mind in hypothetical explanations by the no less fer- 

 tility of ingeniously-devised experiment. Whatever he 

 touched he was sure to draw from it something that it had 

 never before yielded, and he was wholly free from that 

 familiarity which comes to the professed student in every 

 branch of science, and blinds the mental eye to the signi- 

 ficance of things which are overlooked because always 

 in view. 



The simplicity of Mr. Darwin's character pervaded his 

 whole method of work. Alphonse de Candolle visited 

 him in 18S0 and felt the impression of this. "He was 

 not one of those who would construct a palace to lodge a 

 laboratory. I sought out the greenhouse in which so 

 many admirable experiments had been made on hybrids. 

 It contained nothing but a vine." There was no affecta- 

 tion in this. Mr. Darwin provided himself with every 

 resource which the methods of the day or the mechanical 

 ingenuity of his sons could supply, and when it had served 

 its purpose it was discarded. Nor had he any prepossession 

 in favour of one kind of scientific work more than another. 

 His scientific temperament was thoroughly catholic and 

 sympathetic to anything which was not a mere regrinding 

 of old scientific dry bones. He would show his visitors 

 an Epipactis which for years came up in the middle of a 

 gravel walk with almost as much interest as some new 

 point which he had made out on a piece of work actually 

 in hand. And though he had long abandoned any active 

 interest in systematic work, only a few months before his 

 death he had arranged to provide funds for the prepara- 

 tion of the new edition of Steudel's Nomenclator, which, 

 at his earnest wish, has been projected at Kew. 

 {To be continued.') 



MASCART AND JOUBERT'S "ELECTRICITY 



AND MAGNETISM" 



Lemons sitr L' Electricite" et la Magnetisme. Par E. 



Mascart et J. Joubsrt. Tome I. (Paris, 1882.) 



MANY of our readers must already be familiar with 

 the " Electricite" Statique" of M. Mascart. They 

 will therefore turn with high expectations to the perusal 

 of the " Leqons sur 1' Electricite" et le Magne"tisme," of 

 which he is one of the authors. On the whole they will 

 not be disappointed. They will find in it all the limpid 

 clearness, all the vivacity, all the elegance of presenta- 

 tion, both spiritual and material, that characterise the 

 best French text books ; and they will find withal none 

 of the shallowness with which their grudging admirers 

 have been wont to credit them. It is a wonderful national 

 gift that our Gallic neighbours have — their power of 

 scientific exposition. We Britons, with a stray exception, 

 are far behind them ; still farther are our German cousins. 

 Notwithstanding our undoubted kinship in language and 



