BOOK REVIEWS. 



113 



of great value to gardeners. The account of draining land is fuller than 

 usual, and includes particulars of materials used and tools required, together 

 with the cost of the various methods. 



If our readers at any time require information upon any branch of 

 farming it will be well to look into this work, for although much detail 

 is, perhaps necessarily, omitted, yet almost certainly the reader will 

 acquire some useful knowledge respecting his subject. 



u Heredity." By Professor J. A. Thomson, M.A. 8vo., 605 pp. 

 (John Murray, London, 1908.) 6s. net. 



The problems of heredity closely concern all intelligent human beings, 

 whether from the point of view of the breeders of plants or animals, or 

 from that of the future of the human race. Heredity is " the organic 

 or genetic relation between successive generations," and starting with 

 this definition, Professor Thomson has succeeded in producing in this, 

 the latest volume of the Progressive Science Series, a very readable and 

 altogether excellent review of the subject. The author is an ardent 

 disciple of Weismann, and does not attempt to hide his adherence to 

 Weismann's germ-plasm theory, a theory which, to most botanists, does 

 not seem a necessary one ; but, although this is the case, he gives a fair 

 and clear exposition of the other well-known theories which have been 

 propounded to account for the remarkable facts a comparative study 

 of the characters of parents and offspring has made known. Further- 

 more, he examines the results obtained by cytological investigation, by 

 the biometricians, the Mendelians, and other investigators, in a strictly 

 impartial manner. Some of the most interesting chapters to the general 

 reader are. those upon " Reversion and Allied Phenomena," "Telegony," 

 and " Heredity and Disease." But probably the most important general 

 question discussed in the volume is that concerning the transmission of 

 acquired characters from the parent to its offspring. The question is 

 one of the most far-reaching importance, and although some hold that 

 this transmission is the essential fact in evolution, while others deny 

 that such transmission is possible at all, yet an impartial summing up 

 of the facts which are known, putting aside hypotheses, leads cne only 

 to that very useful and very unsatisfactory verdict, that the transmission 

 of acquired characters is " not proven." The question is one which closely 

 touches upon our everyday life, though the external heritage, which is 

 man's, renders his case a very peculiar one, and probably one in which 

 the result of inquiries into the question upon the extent to which such 

 transmission occurs would be obscured by factors difficult to gauge. 

 Indeed the whole question is beset with difficulties, but until it is solved 

 we shall necessarily be working in the dark, and handicapped accordingly. 



Important as an accurate understanding of such points as these is 

 from a sociological standpoint, they are perhaps more readily applied 

 in dealing with cultivated plants and domesticated animals ; and there 

 is abundant need here for their settlement, and this can only be reached 

 after very careful experiment. 



A very useful bibliography concludes the volume, which is provided 

 with a good index. 



vol. xxxiv. i 



