Dec. 8, 1887] 



NATURE 



123 



Optical inactivity may also be due to mutual compen- 

 sation between two asymmetric carbon atoms, of equal 

 and opposite asymmetry, within the molecule itself. This 

 is the case with inactive tartaric acid. 



At the present moment there is no case known which 

 contradicts the foregoing hypothesis. A few substances, 

 which, at the time when the hypothesis was first put 

 forward, were believed to be optically active, and yet 

 contained in their molecule no asymmetric carbon atom, 

 have since been shown to owe their supposed optical 

 activity to impurities. On the other hand, the presence 

 of an asymmetric carbon atom in the formula of an 

 apparently inactive compound has been an indication to 

 chemists that the resolution of the compound into two 

 isomerides of opposite optical activity might be profitably 

 attempted ; and in the long list of such attempts that 

 have been made within the last few years there appears 

 to be no record of failure. 



We have already alluded to M. Pasteur's classical 

 researches on the tartaric acids, in which he not only 

 rendered the Van 't Hoff-Le Bel hypothesis possible by 

 elucidating all the various modes of optical activity and 

 inactivity which it contemplates, but also devised the 

 methods which have so facilitated its experimental 

 development. It only remains to show how near this 

 great investigator came to anticipating the entire 

 hypothesis. In a passage written in i85o, quoted by Prof. 

 Van 't Hofi\, M. Pasteur says, referring to the tartaric 

 acids : — 



" Les atomes de I'acide droit sont-ils group^s suivant les 

 spires d'un hdlice dextrorsum, ou plach aux sommets d' un 

 h'traedre irregulier, ou disposes suivant tel ou tel 

 assemblage dissymdtrique determine .'' Nous ne saurions 

 rdpondre k ces questions. Mais ce qui ne pent etre 

 I'objet d'un doute, c'est qu'il y a groupement des atomes 

 suivant un ordre dissymetrique k I'image non-superpos- 

 able. Ce qui n'est pas moins certain, c'est que les atomes 

 de I'acide gauche realisent prdcisdment le groupement 

 dissymdtrique inverse de celui-ci." 



This is divination indeed \] 



We must content ourselves with merely referring to 

 another portion of the subject — the application of the 

 carbon tetrahedron to the explanation of anomalous cases 

 of isomerism occurring among unsaturated compounds ; 

 of which allo-isomensin, as Prof. Michael has termed 

 it, fumaric and maleic acids may be taken as illustra- 

 tions. This application, first made by Van 't Hoff in 1874, 

 and accepted later by Le Bel, has undergone within the 

 past year an extension of extraordinary importance at the 

 hands of Prof. Wislicenus in his elaborate memoir " Ueber 

 die raumliche Anordnung der Atome in organischen 

 Molekulen und ihre Bestimmung in geometrisch-isomeren 

 ungesattigten Verbindungen " {Abhandl. der Konigl. 

 Sachs. Gesellsch., 1887), of which a very full and appre- 

 ciative summary is given by Prof. Van 't Hoff in the 

 present work. 



The tridimensional formulae of organic chemistry are 

 thus an accomplished fact. The treatment of the subject 

 is still, of course, only statical ; but, taking care not to 

 lose sight of the limitations thus imposed, the method is 

 a perfectly legitimate one. 



F. R. JAPP. 



THE MAMMOTH AND THE FLOOD. 



The Mainnioth atid the Flood: an Attempt to Confront 

 the Theory of Uniformity with the Facts of Recent 

 Geology. By Henry H. Howorth, M.P., F.S.A; 

 (London : Sampson Low and Co., 1887.) 



MR. HOWORTH'S book is not disproportionate to 

 its subject. But even as the mammoth it had a 

 small beginning. It saw light as letters in Naturk. It 

 cast its swaddling-clothes at the British Association. 

 Grown larger, it took passage on board the Geological 

 Magazine, and, as some thought, threatened to swamp 

 that useful but far from bulky periodical. Now, with 

 body and tusks alike full-grown, it comes forth to champion 

 cataclysm and scatter the uniformitarians. 



The book consists partly of facts, partly of theories. 

 The one part is separable from the other, though of course 

 sometimes the facts are regarded in the light of the 

 theories. We will endeavour in our notice to keep them 

 apart. The first chapter of the work a little reminds us 

 of the hors d'osuvre which sometimes precedes a banquet. 

 Appetizing bits, dainty but miscellaneous — the etymology 

 of mammoth, and its identity with behemoth ; griffons and 

 their claws ; fossil unicorns ; dragons' bones ; Indian 

 fabulous beasts ; stories of giants, and their bones : with 

 such subjects is the reader's palate stimulated. The next 

 chapter gives a history of opinion on the subject of the 

 remains of the mammoth and the woolly rhinoceros. The 

 author then discusses the abode and range of the mam- 

 moth in Asia. He considers it to have been limited to the 

 tundras, which must at that time have enjoyed a climate 

 far more temperate than at the present. Then comes an 

 account of the various discoveries of carcasses, either of 

 the mammoth or of the woolly rhinoceros, in Siberia ; 

 followed by the history of the same animals and their 

 associates in Europe. The climate of Europe, when 

 frequented by them, is next discussed, and the facts bear- 

 ing on the extinction of the mammoth are enumerated, 

 particular stress being laid on the evidence of caves and 

 fissures. Palasolithic man is next called into the witness- 

 box, and cross-questioned as to the cause of his disappear- 

 ance. That he was exterminated by Neolithic invaders 

 does not, to the author, seem a satisfactory theory. That 

 he was a victim of the Deluge is a simple explanation. 

 The Old World is now quitted for the New — the two 

 Americas are examined. In each, at no distant time, 

 huge mammals flourished ; their remains are found under 

 circumstances not materially different from those of 

 similar quadrupeds in the Old World. So they also must 

 have perished in like manner : the Deluge was not 

 limited to Siberia nor to the Old World ; it swept alike over 

 tundra and morass, over prairie and pampa ; it inundated 

 the New. Of course the West Indies could not escape ; 

 apparently no corner of the earth eluded the devastating 

 waves, for Australia, Tasmania, and New Zealand tell 

 the like tale of extinguished life, and sudden devastation. 

 Lastly, there is the citation of historical evidence, in the 

 form of brief summaries of the many variations of the 

 widespread tradition of a universal deluge. 



The facts, as indicated by the above statement— which 

 is only a concise summary of the table of contents — 

 cannot wholly be disentangled from the theories, in the 

 light of which they are viewed and in proof of which 



