458 



NATURE 



\Api-il II, 1872 



On the whole wc prefer the author of " What is a Joule ?" 

 to such a man as this, because we believe he does less 

 harm, and is less likely to mislead " able editors." 



There is one grain of comfort even in the imbecilities 

 and inanities of would-be humorous writers in news- 

 papers, that at least they have woke up to the idea that a 

 scientific discovery is worth laughing at. This is a step 

 gained. Twenty years ago, even ten years ago, the name 

 of even so distinguished a scientist as Dr. Joule would 

 have been utterly unknown to the herd of newspaper 

 writers. We must be thankful for even this much ; and 

 look hopefully forward to the good day coming when 

 Science will take her place' by the side of her sisters. Art 

 and Literature, as equaOy deserving of popular culture. 



GRISEBACH'S VEGETATION OF THE 

 GLOBE 

 Die Vegetation der Erde nach Hirer klimatischen Anord- 

 nung : ein Abriss der vergleicheiiden Gcographie der 

 Pflan2ev ; von A. Grisebach. 2 vol. (Leipzig : Engel- 

 mann, 1872.) 

 '"r'HIS important contribution to a branch of the science 

 -I- which, since the publication of A. de Candolle's 

 "Geographic Botanique " and the promulgation of the 

 Darwinian theories, has been daily acquiring greater 

 value in the minds of philosophical naturalists, is the 

 result of long study and persevering accumulation of 

 data on the part of the learned author. Prof Grisebach 

 had already, in the "Linnaja" for 1S38, given his first 

 views on the limitation of natural floras by climatological 

 influences; and since 1840 he has, in his periodical reports 

 on the progress of geographical botany, entered more or 

 less into the principles and conclusions which he has 

 successively entertained or matured. He now supplies us 

 in these volumes with a methodical digest of the facts he 

 has collected, and of the conclusions he would draw from 

 them. The result is a rich store of materials, which future 

 investigators of the subject must necessarily have re- 

 course to, and the arrangement adopted is perhaps the 

 one best calculated to illustrate that branch of it which is 

 more especially indicated by the title, the influence of 

 climate and physical conditions on the stations and areas 

 of species. But to the general naturalist the value of the 

 work as a book of reference is much diminished by two 

 great deficiencies ; there is no summary of the conclu- 

 sions he would draw from the facts he has detailed, and 

 no index to enable the reader to turn to any individual 

 fact, argument, or deduction, which may have struck him 

 in the perusal of above 1,200 closely printed pages. 



The question of the Origin of Species is not entered 

 into, for the author believes that acknowledged facts 

 prove nothing more than the production of varieties 

 through climatological or other influences, but that " how- 

 ever interesting speculations on the genetic connections of 

 organisms may appear, wc abandon the territory of facts 

 when we indulge in conjectures on the origin of more 

 widely separated forms or races, of species, genera, or 

 families of plants or animals." " That the limits between 

 a species and a variety are not always to be strictly de- 

 fined, is no reason," he observes, " why we should ascribe 

 to both an identical process of formation, or that we 

 should regard the forces by which the gradual variations 



of forms are effected as the only ones by which the 

 multiplicity of nature has been produced." 



As far as we have been able to collect the professor's 

 views, his idea seems to be that, whatever may have been 

 its origin, every species now e.xisting on the globe was at 

 some given (or uncertain) time "produced" in one 

 particular spot, the centre of the species, from whence it 

 has, from the natural tendency to multiplication inherent 

 in every organised race, spread in every direction where 

 its progress has not been checked by extraneous caust s, 

 generally by climatological or other physical opposing in- 

 fluences, sometimes by the mere struggle with competing 

 races. Wherever a considerable number of species appear 

 to have had their centres within a limited area, that area 

 is termed a centre of vegetation ( Vegeiations-centrunt) ; 

 where the migration of plants from one or more centres is 

 limited by physical obstructions, by mountain chains, 

 seas, adverse climate, &c., the space thus enclosed is the 

 province (Gcbiet) of a natural flora. For the " centres of 

 vegetation," the author had originally made use of the 

 term " centres of creation " [Sclidpfunas-centren), which 

 he has now abandoned on account of the objections made 

 to it as expressing some definite process of production. 

 " I, at least," he adds, " under an act of creation, never 

 understood anything else than the operation of certain 

 laws of nature, the further knowledge of which is, as yet, 

 withheld from us. Bentham prefers for the term ' centres 

 of vegetation ' that of ' areas of preservation,' when they 

 remain in their original state, as in oceanic is'an.'s, a 

 mode of expression to which we might well be reco.aciled" 

 (p- 523)- With regard to the term Gebiet, the natural 

 translation would be region, but in this instance, with the 

 facility enjoyed by Germans of adopting words of foreign 

 languages, the word " Region " is made use of for areas 

 limited by altitude within the Gebiet. 



The twenty-four botanical provinces of natural floras 

 which Grisebach had already sketched out in Petermann's 

 Mittlieilungen are here necessarily taken in detail, investi- 

 gating under each one— (i) the climate ; (2) the prevailing 

 plant-forms ; (3) the prevailing plant-formations ; (4) the 

 regions, chiefly as to altitude ; and (5) the centres of vege- 

 tation included in the province. For the " plant-forms " 

 he has carried out a classification founded on that of 

 Humboldt, distributing plants under seven heads — (i) 

 woody plants ; (2) succulent plants ; (3) climbers ; (4) 

 epiphytes ; (5) herbs ; (6) grasses — including sedges, 

 reeds, &c. ; (7) cellular plants : each one subdivided into 

 minor groups. The "plant-formations" are tracts of 

 country whose general aspect is characterised by their 

 vegetation, such as forests, heaths, scrubs, deserts, culti- 

 vated tracts, &c. 



The two provinces worked out with the greatest care, 

 and for which the materials here collected rire perhaps the 

 most deserving of study, as being the most ample, and in 

 both cases checked by the personal experience of the 

 author, are the Forest-province (Waldgebiet) of the eastern 

 contment (the greater part of Europe and temperate Asia), 

 and the Mediterranean region ; the one characterised by 

 its vast uniformity, the other by its broken diversity ; in 

 both of which the complicated influences of climate, con- 

 figuration, and soil, have been more carefully observed, 

 recorded, and studied, than in any other quarter of the 

 globe. The Mediterranean region is particularly instruc- 



