October 24, 1895J 



NATURE 



62: 



may be applied. This needle is practically the only 

 instniment used in the profession. 



The height of civilisation in China was reached at the 

 end of the reign of Kang-hi. The gradual decline is 

 supposed to have commenced with the Tartar domination. 



THE FLORA OF THE GALAPAGOS ISLANDS. 

 T^R. (;. B.A.l'R'S theory of the origin of the Galapagos 

 ^^ Islands is too well known to need explanation here: 

 yet it may be briefly designated the theory of subsidence. 

 He argues that the islands were formerly connected with 

 each other, and at an earlier period with the American 

 continent. It is also almost needless to say that this theory 

 has met with an exceedingly hostile reception ; few in- 

 deed accepting it, even as restricted to a former union of 

 the islands themselves. The publication of an account 

 of the botanical collections ' affords an opportunity 

 of examining this theory from a botanical stand- 

 point. For the purposes of the " Botany " of the 

 Cliallcngc)' Expedition, and c\ er since the publica- 

 tion of that work, I hax e collected all the data coming 

 under my notice bearing on the dispersal of plants to con- 

 siderable distances by wind, water, birds or other creatures 

 excepting human. The evidence thus collected sufficiently 

 accounts for the vegetation of low coral islands, and the 

 littoral vegetation of widely separated countries : but it in 

 no way helps to explain the vegetation of the enormously 

 distant islands of the Antarctic seas, for example, or that 

 of the islands of the Galapagos group, to give another 

 instance. 



But these arc not parallel cases ; they are the two 

 extremes in the amount of differentiation in connection 

 with isolation. 



The biological phenomena of the Galapagos Islands 

 left a deeper impression, probably, on the mind of 

 Darwin than those of any other part of the world he 

 visited, and doubtless had much to do with his later con- 

 ception of the origin of species. The fact on which he 

 laid special stress was that the genera, to a very great 

 extent, were the same in all the islands, and the species 

 different in each island. Dr. Baur's much more exten- 

 sive zoological and botanical collections and observations 

 confirm and emphasise the correctness of the view of his 

 illustrious predecessor of fifty years ago. Darwin 

 specially refers to the existence of different species or 

 races of tortoises and mocking-thrushes in many of the 

 islands ; and Baurs examination of the lizards of the 

 genus Tro/iidun/s, from twelve of the islands, rexeals 

 the same condition of things. The botanists bring for- 

 ward F.uphorbia ~,'iiiii)U'a in illustration of this pheno- 

 menon. This species was described by .Sir Joseph 

 Hooker from a single specimen collected by Macrae in 

 .\lbemarle Island, and the author remarks that he 

 " knew of no species with which to compare this highly 

 curious one.'" Dr. Baur collected it extensively in eight 

 of the islands, and the specimens from almost every 

 one of them exhibit distinct racial characteristics. Aca- 

 /Yp/i(t, a genus of the same n.atural order, presents 

 somewhat more pronounced variation in the different 

 islands, which some botanists regard as of specific value ; 

 other botanists as of varietal value only. Whatever status 

 we give these forms, the flora as a whole is a most in- 

 structive and conx incing illustration of evolution. 



A remarkable peculiarity of the (Galapagos flora, as an 

 insular flora, is the almost total absence of endemic 

 genera, for the two or three genera of the Composita: 

 restricted to the islands are so closely allied to .American 

 genera as hardly to count as distinct. Indeed the whole 



^ B. I-. Robinson and J. .\I. lireetiman, in Atturican Journal of Science, 

 vol. 1. pp. 135-149. 



X.B. — Dr. G. Baur wxs attached to the United .States Fish Commisyiion 

 steamer Albatross, and spent nearly three months in the islands, from June 

 10 to .September 6, 1891. 



NO. 1356, VOL. 52] 



flora is so thoroughly American that, apart from geolo- 

 gical difficulties, it might be regarded as a differentiated 

 remnant thereof, rather than derived therefrom, after the 

 supposed elevation of the islands. Analogous conditions 

 and phenomena are repeated in the deep valleys of the 

 great mountain chains of northern India and western 

 China, where, in neighbouring valleys, the genera are to 

 a great extent the same and the species different. 



Returning to Dr. Baur's extensive botanical collections 

 from the Galapagos, it may be mentioned that they 

 yielded about a dozen new species belonging to the pre- 

 dominating genera. 



Looking at the composition of the Galapagos flora, 

 especially with an eye to the probabilities of the transport 

 of the seeds of its constituents, combined with present 

 conditions. Dr. Baur's theor>' seems deserving of more 

 serious consideration than it has hitherto received. My 

 verj- slender knowledge of geology alone prevents me from 

 taking up a more decided position. 



W. BOTTING HeMSLEY. 



THE LATE PROFESSOR HOPPE-SEYLER} 



\\. 

 Hoppc-Seylcrs Work in Pcrlin, 1850 54 and 1856-61. 



IT has already been stated that Hoppe selected as the 

 subject of his inaugural dissertation some observa- 

 tions on the structure of cartilage and on chondrin.'- 

 Chondrin had been first separated and examined by 

 Johannes .M tiller, •'and afterwards by Mulder and Donders. 

 Pursuing' his study of the chemical reactions of the so- 

 called chondrin, Hoppe in 1852^ described its lasvo- 

 rotatory propetty, and showed that when decomposed 

 by long boiling with dilute mineral acids it yields leucine, 

 but neither glycocine nor tyrosine. Still directing his 

 attention to the connective tissues, Hoppe in the follow- 

 ing year published a valuable and interesting paper-' on 

 the structural elements of cartilage, bone, and tooth. 

 \'irchow had shown '' the possibility of isolating the so- 

 called bone corpuscles. Hoppe now alleged facts which 

 seemed to prove that the lacuna; and canaliculi of bone 

 are lined by a tissue resembling elastic tissue, and are 

 left surrounding the bone cells when decalcified bone is 

 boiled in a Papin's digester. Extending his investigation 

 to tooth, Hoppe studied the chemistry' of the organic 

 basis of dentine, and isolated the "dentinal sheaths," 

 which he showed to correspond structurally and chemic- 

 ally to the more internal portion of the ground substance 

 of bone, which may be separated as a distinct investment 

 bordering the lacuna;, canaliculi, and Ha\ ersian canals. 

 There can be no question of the important bearing which 

 these early histologic-chemical researches had upon the 

 development of our knowledge of the relations and 

 affinities of the connective tissues : attention has been 

 drawn to them for this reason, as well as because they 

 differed somewhat in their scope and method from the 

 work with which Hoppe afterwards mainly busied 

 himself 



Passing over three interesting papers on auscultation • 

 and communications of minor importance on chemical 



1 In the fragmentarj- notes which follow, I do not pretend to give a com- 

 plete or entirely consecutive account of Hoppe-Seylcr's labours ; my object 

 IS to draw attention to some of the principal results of hisjife-work, and to 

 indicate in this way his position among those who, during the last half- 

 century, have contributed to the advancement of biological science.— A. G. 



- F. Hoppe, " De Cirtilaginum Slructura el Chondrino nonnulla," Diss.. 

 Inaiig. Berol. 1850. 



5 Job. Mailer, Poggendorff' s Aimalcn, vol. vvxviii. (1836) pp. 395-356. 



■* Hoppe '* Ueber d.is Chondrin und einige seiner Zersit/ungsproducte," 

 Joum.f. Prakt. Chemic, vol. Ivi. (iS5r)p. 129. 



5 Hoppe, " Ueber die Gewcbseiemenle der Knorpel Knoclien iiml Zahne,' 

 Virchow's Archhi, vol. v. (1853) p. 170. 



6 Virchow, " Verhandl. d. Phys. Med. Gcsellschaft zu Wurzburg,' vol. it. 

 p. 152. 



" Virchow's Archiv, vol. vi. (1854) pp. I43-I73. vol. vi. (1854) pp. 331-349, 

 vol. viii. (1855) pp. 250-259. 



