2o6 



NATURE 



\7idy 12, 1877 



other meaning or place in any part of its history than 

 rejuvenescence can explain. Now Styloiiichia pustulafa 

 is amongst the forms the author has seen to conjugate, 

 and as he believes, as a consequence, to become simply 

 more vital and larger for renewed fissipartition. But 

 Engelmann is undoubtedly right in his affirmation, that 

 there is a conjugate state in which these organisms do 

 not again separate, but the pair simply fuse together. 

 One of the writers of this paper has observed it repeatedly 

 under conditions which render error impossible ; this is 

 not the place to consider to what this fusion leads, but it 

 is important as a fact, inasmuch as it throws doubt upon 

 the completeness of the theory of rejuvenescence, even 

 supposing the facts given us by Biitschli led without 

 exception up to it. Biitschli even admits that this process 

 of fusion may happen, but he simply dismisses it as a 

 "very unusual one'' — surely all the more important on 

 this account, inasmuch as we know that in more highly 

 organised creatures not only a long time, but generations 

 may intervene between distinct acts of fertilisation. 



2. It does not follow that if rejuvenescence be rejected 

 to the extent and with the meaning BiitschU gives it, that 

 it must be rejected altogether. He gives us many remark- 

 able facts that deserve further experiment and research ; 

 and it may result, that what he calls rejuvenescence, is one 

 of the many modes by which rapidity of fissiparous multi- 

 plication is in some organisms aided, and the necessity 

 for the true act of fertilisation is made less frequent ; and 



3. It is clear that there are points in the theory of 

 Balbiani which the facts given by Biitschli overturn ; 

 while there are others that certainly remain unshaken, if 

 they be not strengthened. But it is needful to remember 

 that if the facts given by Biitschli wholly invalidated 

 the interpretations of Balbiani the theory advanced by 

 Biitschli by no means follows as a consequence. In the 

 present state of this inquiry we must seek facts indus- 

 triously, and with persistent honesty, and be assured that 

 their accumulation will lead to important issues ; but we 

 shall do well to place theory, however fascinating, in an 

 extremely subordinate place. 



W. H. Dallinger 

 J. Drysdale 



VON RICHTHOFEN'S " CHINA " 



China. Er^ebnisse ci^ener Reisen, mid darauf ge- 

 grilndeter Studien, Von Ferdinand Freiherrn von 

 Richthofen. Band I. (Berlin: D. Reimer, 1877.) 



WE are glad to welcome the appearance of the first 

 volume of this long-promised work from the pen 

 of the well-known geologist and geographer. Baron v. 

 Richthofen. We content ourselves at present with a 

 general account of the work, hoping in an early number 

 to be able to examine it in detail. The author has en- 

 joyed rare facilities for the accumulation of material, and 

 has improved them so thoroughly that the published re- 

 sults of his researches will assume a leading position 

 among the late additions to scientific literature. In i860 

 he accompanied Count Eulenberg on his mission to 

 China and Japan for the purpose of closing commercial 

 treaties between these lands and the German states. On 

 the return of the expedition Baron v. Richthofen lingered 



behind, attracted by the many unsolved problems of the 

 Celestial Empire. Up to 1872 he devoted himself to a 

 systematic, thorough investigation of the geography and 

 geology of China, traversing in the course of seven dif- 

 ferent journeys the whole eastern part of the empire from 

 Canton to Corea, and penetrating westward to the sources 

 of the Yang-tze-Kiang and the frontiers of Thibet. The 

 essential aims of the'traveller were to place on a scientific 

 basis the geography of the land, determining the hypso- 

 metric relations, and the laws governing the conformation 

 of the mountain-chains, to examine the general geological 

 structure, especially in its relations to the great basins of 

 Central Asia, and to study the laws of climatic changes. 

 Other scientific questions received a minor consideration, 

 and the intellectual life of the people was left entirely out of 

 view. The present volume forms little more than an in- 

 troduction to the elaboration of the immense number of 

 observations made during the long series of years, which 

 will form the body of the work. It is mainly occu- 

 pied with an extensive and complete description of the 

 growth of our knowledge with regard to China, forming 

 a valuable index to the literature on this country. No 

 small amount of space is devoted to the book, "Yii- 

 Kung," or imperial geography, forming the sixth in the 

 series of historical works attributed to Confucius, and 

 covering the period 2357-720 B C. The remaining por- 

 tion of the volume is occupied with the geographical 

 relations of China to Central Asia, and contains a 

 most important study of the loess regions of Northern 

 China. They are not only considered in their relations to 

 the saline steppes of Central Asia, but are compared with 

 all the great loess formations known, and supply the 

 basis for an interesting theory with regard to the forma- 

 tion in the one case of fertile valleys, as those of the Nile 

 and Mississippi, and in the other of sandy wastes. 

 Scarcely less valuable is the clear and distinct picture 

 afforded of the whole mountain system of this portion of 

 Asia. The author finds the laws governing the confor- 

 mations so simple, that less time was required to deter- 

 mine the system than would have been necessary for a 

 tenth of the area in Europe. In a closing chapter on the 

 problems of modern scientific geography, the author 

 sharply defines the province of his science, drawing clearly 

 the limits between it and political geography, ethno- 

 graphy, and kindred sciences. The method to be used in 

 the solution of these problems he defines as " the unin- 

 terrupted consideration of the causal, mutual relations 

 between the earth's surface from its various points of 

 view, terrestrial physics, and the atmosphere on the one 

 side, and between these elements and the organic world 

 in its broadest sense on the other side." Of the three 

 volumes yet to appear, one will be devoted to palreonto- 

 logy, in which the author will be assisted by Dr. Kayser, 

 Dr. Schwager, Prof Schenk, and other able geologists 

 The remaining two will contain the author's extended 

 researches into the coal-fields of China, regarded by him 

 as more valuable than the deposits in the United States of 

 America— the geological structure of the land, the climatic 

 phenomena, the population as affected by these two 

 agencies, the river svstem, means of transport by land 

 and water, chief productions, mercantile possibilities, &c. 

 A generous grant from the Emperor of Germany has per- 

 mitted the publication of the work in a most sumptuous 



