270 



NATURE 



[July 20, 1893 



I know nothing in scientific literature more entertaining 

 and instructive than his Mcinoires and Souvenirs. They 

 supply a striking instance of his irresistible influence. 

 The return of an important collection of original drawings 

 of Mexican plants was demanded by the lender. De 

 Candolle roused the whole of Genevan society to his aid ; 

 the city was almost in a ferment till by united co-opera- 

 tion every one of the 1200 drawings had been copied. 



The fa:cts to be told of Alphonse de Candolle's life are 

 simple. Born October 27, 1 806, at Paris, he took the degree 

 of Bachelor of Science at Geneva in 1825, and of Doctor of 

 Laws with great distinction in 1829. The influence of his 

 legal training probably gave an impress to his work and 

 character all through life. In 1831 he began to assist his 

 father in his duties as Professor of Botany, and he suc- 

 ceeded him in the chair in 1835. He held it till 1850, 

 when he left it, owing to political events. The remainder 

 of his life he passed as a private man of science. But 

 during middle life he fulfilled with dignity, and not with- 

 out influence, the duties of a citizen which his character 

 and social position in some sort imposed upon him. After 

 serving as a member of the Representative Council of 

 Geneva, he was a member of the Grand Council from 

 1862 to 1866. He was the first to advocate the " referen- 

 dum " in political affairs ; he exerted himself to effect 

 numerous reforms in economic and sanitary matters ; and 

 by obtaining the use of postage-stamps for his Canton he 

 appears to have paved the way for their general intro- 

 duction into Switzerland. 



The earliest and perhaps the best of De Candolle's 

 botanical works is his Monograph of the Cainpamilacece, 

 published in 1831. It has stood its ground more solidly 

 than is often the case with the taxonomic work of the 

 time, and its conclusions have been in the main adopted 

 in the later revision of the order by Bentham and 

 Hooker. 



In 1841 De Candolle's father died. He had com- 

 menced the publication of the Prodroinus in 1824. The 

 object of this vast undertaking was to give brief diag- 

 nostic descriptions of all known plants. Its publication 

 finally settled the question which had long agitated the 

 scientific world as to the supersession of the artificial 

 Linnean system by a natural one. What is called the 

 Candollean sequence is still in general use, though it is con- 

 fessedly in some respects itself artificial, and only an 

 approximation to a truly natural arrangement. The 

 father had published seven volumes of this classical and 

 indispensable work. The son carried it down to the 

 completion of the Dicotyledons in the seventeenth volume, 

 published in 1873. He saw that no one man could carry 

 out the task single-handed. While formulating a uniform 

 plan and method of procedure, he managed to summon 

 to his aid the systematic botanists of all Europe. 

 In 1847 he was able to claim that he had contri- 

 butors from England to the Tyrol, and from Montpellier to 

 the Baltic. He took himself no mean share of the work, 

 and if this kind of research affords comparatively little 

 opportunity for the display of genius, Alphonse de Can- 

 dolle's work is always characterised by qualities of work- 

 manlike accuracy and scholarly finish. 



In early life the writings of Humboldt inspired De 

 Candolle, as they have done many young men, with the 

 impulse to travel. Family circumstances, however, forbad 

 it. But the fascination of phyto-geographical problems 

 had taken possession of him, and the vast assemblage of 

 specific forms which continually passed through his hands 

 must have supplied him with inexhaustible food for 

 reflection. 



In 1855 appeared his Geographic botanique raisonnc'e, 

 which was the most important work of his life. It would be 

 impossible in a short spaceto appreciate this justly. Ithas 

 been complained that it led to no direct conclusion ; and 

 it is all but inexplicable that the author missed seeing 

 that the immense mass of facts he had collected really 



NO. 1238. VOL. 48] 



pointed directly to evolution as the key to its explanation. 

 But the character of the man is an element which must>, 

 not be overlooked. Essentially in method a statistician, ' 

 he believed these facts, properly marshalled, would evolve 

 their own law. But scientific method, like other calcu- 

 lating machines, will not evolve more than is implicitly 

 put into it. De Candolle, it must be admitted, neither 

 possessed nor had much sympathy with that touch of 

 imagination akin to inspiration, which by some un- 

 conscious cerebral integration sees an even wider prin- 

 ciple underlying the facts which are contemplated than 

 by any method of manipulation can be educed from them. 

 But it maybe doubted whether a study of the Distribu- 

 tion problem would ever have led to evolution directly. 

 The essence of the Darwinian theory was the discovery 

 of a possible, at any rate conceivable, modus operandi. 

 This was the result of an attack from the biological side. 

 The phenomena on a large scale which geographical 

 distribution present are too remote from their ultimate 

 cause to immediately suggest it ; yet when the principle 

 is grasped they are immediately susceptible of deductive 

 explanation. 



Nevertheless, I cannot but regard the Geographic, if 

 not as an actual precursor, yet as one of the inevitable 

 foundation-stones of the modern evolution-principle. 

 In the first place, De Candolle dealt more than one 

 heavy blow to Lamarckism. Botanists were impregnated 

 with the idea that plant-distribution was a mere matter 

 of temperature. Adanson had supposed that there 

 was a simple numerical relation between it and growth. 

 Boussingault had gone further and stated that the product 

 of the period of growth multiplied into the mean temp- 

 erature was a constant. That within limits there is 

 truth in these statements, I myself believe, and for 

 cultural staples the problem is still worth fresh investiga- 

 tion. But the facts will not bear generalisation, and in 

 the field of nature De Candolle saw that they explained 

 little. Other factors, such as light and moisture, must 

 also be taken into account ; if he had gone a little 

 further he would have met the " Struggle for Existence." 



But De Candolle's most fertile conclusion was the 

 derivative nature of existing floras, and he cites with 

 approval the classical speculations of Edward Forbes 

 on the flora of Western Europe. De Candolle at any 

 rate brought together a mine of accurate information, 

 collected with vast labour without prepossession and 

 marshalled with consummate judgment. He has furnished 

 an armoury from which it will be long before successive 

 students of the subject cease to draw their weapons. 

 Had he taken narrow and pedantic views of specific 

 limitations, he would have left the subject more confused 

 than he found it. But by treating, for example, the 

 aquatic Ranunculi as a group of variable forms of a 

 single species, Ranunculus aquatilis, he supplies facts 

 in a shape at once available for the Darwinian student. 



De Candolle met Darwin in 1839, and though he main- 

 tained a correspondence with him, they did not meet 

 again till 1880, when the former paid a visit to town. 

 Of this he published a touching and in some degree 

 pathetic account in 18S2. He makes his submission to 

 the inevitable. I will translate a few words : — 



"The existing distribution of species, especially in 

 islands, compelled me to admit, as early as 1 855, four years 

 before the appearance of the " Origin of Species," the 

 creation, in certain cases, of new specific forms derived 

 from older ones. I proved to demonstration that the 

 majority of species ascend to periods far more remote than 

 is generally supposed, and that they have passed through 

 both geological and climatic changes. Lyell accustomed 

 geologists to consider small causes, operating through 

 long periods, as competent to produce large effects. The 

 astronomical conception of indefinite time had penetrated 

 natural science. Five or six thousand years counted for 

 little in the history of organised beings. . . . L'ncertainty 



