BOOK REVIEWS. 



233 



The translator and editor have interpolated nothing in the text, and 

 for this abstention they deserve our thanks, for the result has been to 

 give us a master's conclusions based upon comprehensiveness of detail 

 and an accuracy of observation such as one man is rarely able to combine, 

 in English singularly free from that Teutonic form which is so difficult 

 to avoid in translating from the German. The result is a work which 

 every geologist must read and the conclusions in which he must weigh 

 with all due care and reverence. The maps, plates, and other illustrations 

 — many of the last woodcuts — are admirable. 



" Mendel's Principles of Heredity." By Professor W. Bateson, M.A., 

 F.R.S., V.M.H. 8vo., 396 pp., 3 portraits, 6 plates, 23 figs. (University 

 Press, Cambridge, 1909.) 12s. net. 



This volume must be considered as the best and most authoritative 

 text book of Mendelisru that has yet been published. 



It contains a short biography of Mendel and translations of the two 

 important papers (on Hybridization and on Hieracium) upon which the 

 whole structure of Mendelism is founded. There is a long bibliography 

 and a summary of the various characters (61 pairs) which have been 

 the subject of experiment. Some of the chapters, such as those on com- 

 pound characters, on heredity and sex, on double flowers, and on heredity 

 in man may interest horticulturists, but the most important in this 

 respect are the five chapters entitled " Heredity in Colour" and the one 

 on "Practical Applications." 



By way of showing the importance of breeding from the first crosses 

 the author gives a beautiful plate illustrating the extraordinary variations 

 in the second generation in the case of two strains of Primula sinensis. 

 The first cross was a dull and uninteresting flower, but in the second 

 generation many of the blooms were richly coloured and showed in- 

 teresting variations. The rest of this chapter deals with breeding from 

 single seeds and with precautions against insect pollination. 



There are full accounts of those valuable experiments of Miss 

 Saunders and Miss Wheldale which have greatly advanced our knowledge 

 of flower-colours. It would be gratifying to know if other experiments 

 are being carried out not so much in support of Mendelism as to increase 

 our information on this important subject. There are also the interest- 

 ing experiments of Prof. Bateson himself, who found that a richly 

 coloured sweet pea of the " Purple Invincible " type resulted from a cross 

 of two white sweet peas both entirely without colour. We have not 

 discovered any reference to Mr. Hurst's experiment with Golden Queen 

 and Fireball tomatos which is one of the clearest and most interesting 

 in this connection. 



On the other hand, Mr. Hurst's suggestion that the " presence of 

 something ' ' is usually the dominant and its absence the recessive character 

 is, as we are glad to observe, frankly accepted by Prof. Bateson. 



It is not too much to say that for all who are interested in the 

 hybridizing of flowers, these chapters on colour are of the first im- 

 portance. 



But it is at least probable that those who try to understand and 

 appreciate them, must be prepared for severe mental exercise, for 



VOL. XXXV. R 



