January 27, 192 1] 



NATURE 



689 



Mr. Woods and Dr. Morley Davies are, as in- 

 structors of youth, chiefly concerned to get some 

 facts into the heads of their pupils. They have 

 not much space for philosophic discussion (what 

 they have they make good use of), and none at 

 all for that general talk which can brighten the 

 way or inspire the reader to further effort. 

 Whichever of them you choose to follow as 

 guide, you will be well advised to take Mr. 

 Hawkins with you as philosopher and friend. 

 His drawings and photographs are admirable, 

 .tnd, considering the price of the book, are as 

 much a credit to the publisher as to his own skill. 

 They will greatly help the reader who has not at 

 hand the more purely descriptive works, or whose 

 acquaintance with fossils is not already that 

 which seems demanded by some of the chapters. 

 The chapter on materials explains the nature of 

 fossils and distinguishes the various modes of 

 preservation and their relation to different kinds 

 of rocks. Thus it answers questions constantly 

 asked by the casual finder of fossils. Is it, how- 

 ever, quite true that amber inclusa represent "the 

 most perfect type of preservation " ? Were, this 

 so, it should be possible to dissolve out the organ- 

 isms and to remount them in a manner more con- 

 venient for study. He who attempts this will 

 find that there is nothing to get out. What one 

 sees in the amber is but an imprint— the ghost, as 

 it were, of some insect, the material body of 

 which has vanished. The preservation of chitin 

 in some fine clays, as of the Oesel Eurypterus, is 

 really more complete. 



Again, to apply the term "cast" to an external 

 imprint, and the term " mould " to an internal fill- 

 ing of some dissolved shell, seems to reverse the 

 ordinary usage. Here Dr. Davies and Mr. 

 Woods more nearly approach accuracy. There 

 are four ca.ses to distinguish : a single valve of 

 a mussel may leave in the rock an external im- 

 print or impression, and an internal imprint ; the 

 complete shell of a mussel or a snail, or the test 

 of a sea-urchin, may have been dissolved away, 

 leaving the complete external mould (from which 

 a plaster cast can be taken) and the complete in- 

 filling of matrix (which is a natural cast of the 

 interior). 



The geological distribution and the succession 

 of life-forms, which constitute the real basis of 

 pala;onfology as an independent science, are at- 

 tended to by Mr. Woods in paragraphs under 

 the zoological divisions, and are summarised by 

 Dr. Davies in a compact but clear appendix. 

 Under the heading " Historical Biology " they 

 make up the second half of Mr. Hawkins's book. 

 H^nyone who has attempted a similar history 

 ^Hnows how hard it is to vary the phrasing, to 

 ^E NO. 2674, VOL. 106] 



bring out the broad masses, and to avoid a mere 

 list of names. " Lucina and Corbis are common 

 throughout the era. Cyclodonts are abundantly 

 illustrated by Cardiidae, Protocardia and Discors 

 are especially frequent in the Eocene, Cardium 

 itself is common in the Crags. Teleodonts are 

 the predominant forms. Venus (pi. xvi.. Fig. i), 

 Dosinia (pi. xvi., Fig. 2), Meretrix and Paphia 

 have numerous species in the later Cainozoic; 



Teliina, Macoma, Psammobia and " but, no ! 



the pen denies its office. Let us rather turn back 

 to the interesting chapters "Geological Palaeon- 

 tology" and "Biological Palaeontology," where 

 the author shows what light may be thrown by 

 fossils on climatic and other conditions at diverse 

 times and places, and on the problems of phylo- 

 geny, morphogeny, specialisation, degeneration, 

 and orthogenesis. 



The profound studies of Echinoidea by Mr. 

 Hawkins entitle his opinions on those difficult 

 questions to the utmost respect. But, dealing as 

 we are here with educational books, we prefer to 

 conclude with an opinion based on his successful 

 work as teacher, an opinion with which examiners 

 ought to agree. Recognition of species (fossil- 

 spotting) should not be demanded of average 

 students. "The chronological distribution of 

 families and genera will give ample precision for 

 elementary needs." "The most elementary student 

 ought to know that Ammonites are not found in 

 Cainozoic rocks; but he ought not to know the 

 difference between Dactylioceras commune and 

 Peronoceras aimulatum. If the latter detail has 

 been forced into his unprepared mind, some point 

 of more general application and greater import- 

 ance must have been omitted or ejected." 



F. A. B.\THER. 



Sugar Technology and Fermentation, 

 (i) The Sugar-beet in America. By Prof. F. S. 

 Harris. (The Rural Science Series, edited by 

 L. H. Bailey.) Pp. xviii-*-342 + xxxii plates. 

 (New York : The Macmillan Co. ; London : 

 Macmillan and Co., Ltd., 1919.) Price 121. net. 



(2) The Manufacture of Sugar from the Cane and 

 Beet. By T. H. P. Heriot. (Monographs on 

 Industrial Chemistry, edited by Sir Edward 

 Thorpe.) Pp. x-f436. (London: Longmans, 

 Green, and Co., 1920.) Price 24s. net. 



(3) The Carbohydrates and Alcohol. By Dr. S. 

 Rideal and Associates. (Industrial Chemistry.) 

 Pp. XV -I- 2 19. (London: Baillitrc, Tindall, and 

 Cox, 1920.) Price 12s. 6d. net. 



(0 HTHE beet-sugar industry in North America 

 is of comparatively recent date, although 

 It was undertaken nearly a century ago by men, 



